diff --git a/src/app/(app)/__tests__/init-session-generation.test.tsx b/src/app/(app)/__tests__/init-session-generation.test.tsx
new file mode 100644
index 00000000..28589ee8
--- /dev/null
+++ b/src/app/(app)/__tests__/init-session-generation.test.tsx
@@ -0,0 +1,140 @@
+/**
+ * Signing out while app initialization is still awaiting must retire that run: a stale
+ * invocation may not mark the app initialized, connect the chat hub, or restart location
+ * tracking that the sign-out cleanup just stopped.
+ *
+ * The layout itself pulls in Mapbox, Novu, push notifications and the whole store graph,
+ * so the guard protocol is exercised through the same generation-token shape the layout
+ * uses rather than by rendering it.
+ */
+import { act, renderHook } from '@testing-library/react-native';
+import React from 'react';
+
+interface Deferred {
+  promise: Promise<void>;
+  resolve: () => void;
+}
+
+function deferred(): Deferred {
+  let resolve: () => void = () => undefined;
+  const promise = new Promise<void>((res) => {
+    resolve = res;
+  });
+  return { promise, resolve };
+}
+
+/** Mirrors the layout's initializeApp guard: generation captured at start, checked after each await. */
+function useInitGuard(gate: Deferred, effects: { connectHub: jest.Mock; startLocation: jest.Mock; markInitialized: jest.Mock }) {
+  const initGeneration = React.useRef(0);
+  const isInitializing = React.useRef(false);
+
+  const initialize = React.useCallback(async () => {
+    if (isInitializing.current) return;
+    isInitializing.current = true;
+    const generation = (initGeneration.current += 1);
+    const isCurrentRun = () => initGeneration.current === generation;
+
+    try {
+      await gate.promise;
+      if (!isCurrentRun()) return;
+
+      effects.connectHub();
+      if (!isCurrentRun()) return;
+
+      effects.markInitialized();
+      if (!isCurrentRun()) return;
+
+      effects.startLocation();
+    } finally {
+      if (isCurrentRun()) {
+        isInitializing.current = false;
+      }
+    }
+  }, [gate, effects]);
+
+  const signOut = React.useCallback(() => {
+    initGeneration.current += 1;
+    isInitializing.current = false;
+  }, []);
+
+  return { initialize, signOut, isInitializing };
+}
+
+describe('app initialization session generation', () => {
+  const effects = { connectHub: jest.fn(), startLocation: jest.fn(), markInitialized: jest.fn() };
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('abandons an in-flight run when the session ends mid-initialization', async () => {
+    const gate = deferred();
+    const { result } = renderHook(() => useInitGuard(gate, effects));
+
+    let pending: Promise<void> = Promise.resolve();
+    act(() => {
+      pending = result.current.initialize();
+    });
+
+    // Sign-out lands while initialization is still awaiting its first step.
+    act(() => {
+      result.current.signOut();
+    });
+
+    await act(async () => {
+      gate.resolve();
+      await pending;
+    });
+
+    expect(effects.connectHub).not.toHaveBeenCalled();
+    expect(effects.markInitialized).not.toHaveBeenCalled();
+    expect(effects.startLocation).not.toHaveBeenCalled();
+  });
+
+  it('completes normally when the session survives', async () => {
+    const gate = deferred();
+    const { result } = renderHook(() => useInitGuard(gate, effects));
+
+    let pending: Promise<void> = Promise.resolve();
+    act(() => {
+      pending = result.current.initialize();
+    });
+
+    await act(async () => {
+      gate.resolve();
+      await pending;
+    });
+
+    expect(effects.connectHub).toHaveBeenCalledTimes(1);
+    expect(effects.markInitialized).toHaveBeenCalledTimes(1);
+    expect(effects.startLocation).toHaveBeenCalledTimes(1);
+  });
+
+  it('frees the in-progress guard so the next sign-in can initialize', async () => {
+    const first = deferred();
+    const { result } = renderHook(() => useInitGuard(first, effects));
+
+    let pending: Promise<void> = Promise.resolve();
+    act(() => {
+      pending = result.current.initialize();
+    });
+    act(() => {
+      result.current.signOut();
+    });
+
+    // The new session starts before the retired run has settled.
+    let second: Promise<void> = Promise.resolve();
+    act(() => {
+      second = result.current.initialize();
+    });
+
+    await act(async () => {
+      first.resolve();
+      await Promise.all([pending, second]);
+    });
+
+    // Exactly one run reached the effects: the current one.
+    expect(effects.markInitialized).toHaveBeenCalledTimes(1);
+    expect(effects.startLocation).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/app/(app)/_layout.tsx b/src/app/(app)/_layout.tsx
index 42168733..ea3289ff 100644
--- a/src/app/(app)/_layout.tsx
+++ b/src/app/(app)/_layout.tsx
@@ -83,6 +83,10 @@ export default function TabLayout() {
   // Refs to track initialization state
   const hasInitialized = useRef(false);
   const isInitializing = useRef(false);
+  // Bumped on every initialization start and whenever the session ends. An in-flight run
+  // compares its captured value after each await, so a run belonging to a session that is
+  // over can no longer connect hubs or mark the app initialized.
+  const initGeneration = useRef(0);
   const hasHiddenSplash = useRef(false);
   const parentRef = useRef(null);
 
@@ -151,6 +155,8 @@ export default function TabLayout() {
     }
 
     isInitializing.current = true;
+    const generation = (initGeneration.current += 1);
+    const isCurrentRun = () => initGeneration.current === generation;
     logger.info({
       message: 'Starting app initialization',
       context: {
@@ -167,10 +173,14 @@ export default function TabLayout() {
       // time-to-interactive (previously 8+ serial network hops).
       await Promise.all([useRolesStore.getState().init(), useCallsStore.getState().init(), useWeatherAlertsStore.getState().init(), securityStore.getState().getRights(), featureFlagsStore.getState().fetchFlags()]);
 
+      if (!isCurrentRun()) return;
+
       // SignalR needs config (EventingUrl) and rights (DepartmentId) — both
       // available now. The two hub connects are independent.
       await Promise.all([useSignalRStore.getState().connectUpdateHub(), useSignalRStore.getState().connectGeolocationHub()]);
 
+      if (!isCurrentRun()) return;
+
       // Connect the realtime chat hub only when the Chat.System feature flag is on for
       // this department; when it is off every chat surface stays hidden.
       if (featureFlagsStore.getState().isEnabled(FeatureFlagKeys.ChatSystem)) {
@@ -189,6 +199,8 @@ export default function TabLayout() {
         });
       }
 
+      if (!isCurrentRun()) return;
+
       hasInitialized.current = true;
 
       // Evict expired/capped API cache entries once per cold start.
@@ -223,12 +235,20 @@ export default function TabLayout() {
           context: { error },
         });
       }
+      // A run whose session already ended must not burn the retry budget or clobber
+      // state a newer run has since established.
+      if (!isCurrentRun()) return;
+
       // Reset initialization state on error so it can be retried
       hasInitialized.current = false;
       setInitRetryCount((c) => c + 1);
     } finally {
-      isInitializing.current = false;
-      setIsInitComplete(true);
+      // Only the current run owns the guard; a superseded run clearing it would let two
+      // initializations overlap.
+      if (isCurrentRun()) {
+        isInitializing.current = false;
+        setIsInitComplete(true);
+      }
     }
   }, [status]);
 
@@ -270,7 +290,15 @@ export default function TabLayout() {
   // Handle app initialization - simplified logic
   const MAX_INIT_RETRIES = 3;
   useEffect(() => {
-    if (status !== 'signedIn' && initRetryCount > 0) {
+    if (status === 'signedIn') return;
+
+    // Leaving the signed-in state retires any initialization still in flight, and frees
+    // the guard it no longer owns so the next sign-in is not skipped as "already
+    // initializing".
+    initGeneration.current += 1;
+    isInitializing.current = false;
+
+    if (initRetryCount > 0) {
       setInitRetryCount(0);
     }
   }, [status, initRetryCount]);
diff --git a/src/app/(app)/chatbot.tsx b/src/app/(app)/chatbot.tsx
index 1905466b..51b21837 100644
--- a/src/app/(app)/chatbot.tsx
+++ b/src/app/(app)/chatbot.tsx
@@ -8,9 +8,7 @@ import { copyToClipboard } from '@/components/chat/chat-utils';
 import { MessageActionsSheet } from '@/components/chat/message-actions-sheet';
 import { MessageBubble } from '@/components/chat/message-bubble';
 import { TypingDots } from '@/components/chat/typing-indicator';
-import { Actionsheet, ActionsheetBackdrop, ActionsheetContent, ActionsheetDragIndicator, ActionsheetDragIndicatorWrapper } from '@/components/ui/actionsheet';
 import { Box } from '@/components/ui/box';
-import { Button, ButtonText } from '@/components/ui/button';
 import { Center } from '@/components/ui/center';
 import { FlatList } from '@/components/ui/flat-list';
 import { FocusAwareStatusBar } from '@/components/ui/focus-aware-status-bar';
@@ -20,7 +18,6 @@ import { KeyboardAvoidingView } from '@/components/ui/keyboard-avoiding-view';
 import { Pressable } from '@/components/ui/pressable';
 import { Spinner } from '@/components/ui/spinner';
 import { Text } from '@/components/ui/text';
-import { Textarea, TextareaInput } from '@/components/ui/textarea';
 import { VStack } from '@/components/ui/vstack';
 import { type ChatMessageResultData } from '@/models/v4/chat';
 import useAuthStore from '@/stores/auth/store';
@@ -40,8 +37,6 @@ export default function ChatbotScreen() {
   const isModerator = !!securityStore((s) => s.rights)?.IsAdmin;
   const [text, setText] = useState('');
   const [actionsMessage, setActionsMessage] = useState<ChatMessageResultData | null>(null);
-  const [editMessage, setEditMessage] = useState<ChatMessageResultData | null>(null);
-  const [editText, setEditText] = useState('');
 
   useFocusEffect(
     useCallback(() => {
@@ -72,7 +67,14 @@ export default function ChatbotScreen() {
 
   const renderItem = useCallback(
     ({ item }: { item: ChatMessageResultData }) => (
-      <MessageBubble message={item} isOwn={!!item.SenderUserId && item.SenderUserId === currentUserId} showSender={false} currentUserId={currentUserId} onLongPress={setActionsMessage} onToggleReaction={() => undefined} />
+      <MessageBubble
+        message={item}
+        isOwn={!!item.SenderUserId && item.SenderUserId === currentUserId}
+        showSender={false}
+        currentUserId={currentUserId}
+        onLongPress={setActionsMessage}
+        onToggleReaction={() => undefined}
+      />
     ),
     [currentUserId]
   );
@@ -122,7 +124,9 @@ export default function ChatbotScreen() {
         ) : (
           <FlatList
             data={ordered}
-            maintainVisibleContentPosition={{ startRenderingFromBottom: true }}
+            // autoscrollToBottomThreshold is off by default in FlashList v2; without it a
+            // new answer lands below the viewport, hidden behind the input row.
+            maintainVisibleContentPosition={{ startRenderingFromBottom: true, autoscrollToBottomThreshold: 0.2 }}
             keyExtractor={(item: ChatMessageResultData) => item.ChatMessageId}
             renderItem={renderItem}
             contentContainerStyle={{ paddingVertical: 8 }}
@@ -150,7 +154,7 @@ export default function ChatbotScreen() {
         </HStack>
       </KeyboardAvoidingView>
 
-      {/* Restricted actions for assistant messages: copy, edit own, pin (moderator), flag. */}
+      {/* Restricted actions for assistant messages: copy, pin (moderator), flag. */}
       <MessageActionsSheet
         message={actionsMessage}
         isOpen={actionsMessage !== null}
@@ -164,42 +168,12 @@ export default function ChatbotScreen() {
           const ok = await copyToClipboard(m.Body ?? '');
           useToastStore.getState().showToast(ok ? 'success' : 'info', ok ? t('chat.copied') : t('chat.copy_unavailable'));
         }}
-        onEdit={(m) => {
-          setEditMessage(m);
-          setEditText(m.Body ?? '');
-        }}
+        onEdit={() => undefined}
         onDelete={() => undefined}
         onFlag={(m, reason) => useChatStore.getState().flagMessage(m.ChatMessageId, reason)}
         onTogglePin={(m, pinned) => chatbotChannelId && useChatStore.getState().togglePin(m.ChatMessageId, chatbotChannelId, pinned)}
         onModeratorDelete={() => undefined}
       />
-
-      {/* Edit own message */}
-      <Actionsheet isOpen={editMessage !== null} onClose={() => setEditMessage(null)}>
-        <ActionsheetBackdrop />
-        <ActionsheetContent>
-          <ActionsheetDragIndicatorWrapper>
-            <ActionsheetDragIndicator />
-          </ActionsheetDragIndicatorWrapper>
-          <VStack className="w-full p-2" space="md">
-            <Text className="text-base font-semibold text-typography-900">{t('chat.edit_message')}</Text>
-            <Textarea>
-              <TextareaInput value={editText} onChangeText={setEditText} multiline />
-            </Textarea>
-            <Button
-              className="bg-primary-600"
-              onPress={() => {
-                if (editMessage && chatbotChannelId && editText.trim()) {
-                  void useChatStore.getState().editMessage(editMessage.ChatMessageId, chatbotChannelId, editText.trim());
-                }
-                setEditMessage(null);
-              }}
-            >
-              <ButtonText>{t('chat.save')}</ButtonText>
-            </Button>
-          </VStack>
-        </ActionsheetContent>
-      </Actionsheet>
     </Box>
   );
 }
diff --git a/src/app/_layout.tsx b/src/app/_layout.tsx
index 5b57ce0d..77787029 100644
--- a/src/app/_layout.tsx
+++ b/src/app/_layout.tsx
@@ -50,9 +50,15 @@ const navigationIntegration = Sentry.reactNavigationIntegration({
   enableTimeToInitialDisplay: false,
 });
 
+// Sentry's own logger is off by default: watchdog-termination tracking rewrites the
+// native scope on every RNSentry turbo-module call, so `debug` floods the Metro
+// console with hundreds of "Writing tags to disk" lines a second. Flip to `__DEV__`
+// temporarily when diagnosing Sentry itself.
+const SENTRY_DEBUG = false;
+
 Sentry.init({
   dsn: Env.SENTRY_DSN,
-  debug: __DEV__, // Only debug in development, not production
+  debug: SENTRY_DEBUG,
   tracesSampleRate: __DEV__ ? 0.1 : 0.2, // 10% in dev (low to avoid setTimeout wrapping overhead), 20% in production
   profilesSampleRate: __DEV__ ? 0.1 : 0.2, // 10% in dev, 20% in production
   sendDefaultPii: false,
diff --git a/src/app/chat/[channelId].tsx b/src/app/chat/[channelId].tsx
index 423e5399..24cbd0ad 100644
--- a/src/app/chat/[channelId].tsx
+++ b/src/app/chat/[channelId].tsx
@@ -7,7 +7,7 @@ import { Platform } from 'react-native';
 
 import { getPresence, uploadAttachment } from '@/api/chat/chat';
 import { AckBanner } from '@/components/chat/ack-banner';
-import { copyToClipboard, getChannelDisplayName, getImageMimeType } from '@/components/chat/chat-utils';
+import { buildGifMetadata, buildLocationMetadata, copyToClipboard, getChannelDisplayName, getImageMimeType } from '@/components/chat/chat-utils';
 import { GifPickerSheet } from '@/components/chat/gif-picker-sheet';
 import { MessageActionsSheet } from '@/components/chat/message-actions-sheet';
 import { MessageBubble } from '@/components/chat/message-bubble';
@@ -155,7 +155,7 @@ export default function ChannelConversationScreen() {
   const handleSendGif = useCallback(
     (gif: GifResultData) => {
       if (!channelId) return;
-      const metadata = JSON.stringify({ GifUrl: gif.GifUrl, PreviewUrl: gif.PreviewUrl, Width: gif.Width, Height: gif.Height, Title: gif.Title });
+      const metadata = buildGifMetadata(gif);
       void useChatStore.getState().sendMessage({ channelId, body: gif.Title ?? 'GIF', messageType: ChatMessageType.Gif, metadataJson: metadata });
     },
     [channelId]
@@ -164,7 +164,7 @@ export default function ChannelConversationScreen() {
   const handleSendLocation = useCallback(
     (latitude: number, longitude: number, urgent: boolean) => {
       if (!channelId) return;
-      const metadata = JSON.stringify({ Latitude: latitude, Longitude: longitude });
+      const metadata = buildLocationMetadata(latitude, longitude);
       void useChatStore.getState().sendMessage({
         channelId,
         body: t('chat.shared_location'),
@@ -312,7 +312,9 @@ export default function ChannelConversationScreen() {
         ) : (
           <FlatList
             data={ordered}
-            maintainVisibleContentPosition={{ startRenderingFromBottom: true }}
+            // autoscrollToBottomThreshold is off by default in FlashList v2; without it a
+            // sent/incoming message lands below the viewport, hidden behind the composer.
+            maintainVisibleContentPosition={{ startRenderingFromBottom: true, autoscrollToBottomThreshold: 0.2 }}
             keyExtractor={keyExtractor}
             renderItem={renderItem}
             onStartReached={handleStartReached}
@@ -354,7 +356,7 @@ export default function ChannelConversationScreen() {
           handleToggleReaction(
             m,
             emoji,
-            m.Reactions.some((r) => r.Emoji === emoji && r.UserId === currentUserId)
+            (m.Reactions ?? []).some((r) => r.Emoji === emoji && r.UserId === currentUserId)
           )
         }
         onReply={openThread}
diff --git a/src/app/chat/thread/[messageId].tsx b/src/app/chat/thread/[messageId].tsx
index 537c4ab6..99cb6116 100644
--- a/src/app/chat/thread/[messageId].tsx
+++ b/src/app/chat/thread/[messageId].tsx
@@ -4,6 +4,7 @@ import { useTranslation } from 'react-i18next';
 import { Platform } from 'react-native';
 
 import { getThread } from '@/api/chat/chat';
+import { buildLocationMetadata } from '@/components/chat/chat-utils';
 import { MessageBubble } from '@/components/chat/message-bubble';
 import { MessageComposer } from '@/components/chat/message-composer';
 import { Box } from '@/components/ui/box';
@@ -61,10 +62,6 @@ export default function ThreadScreen() {
     [channelId, messageId]
   );
 
-  const handleSendGif = useCallback(() => {
-    // GIFs in threads are sent as text-less messages via the composer's gif flow; kept minimal here.
-  }, []);
-
   const handleSendLocation = useCallback(
     (latitude: number, longitude: number, urgent: boolean) => {
       if (!channelId || !messageId) return;
@@ -72,7 +69,7 @@ export default function ThreadScreen() {
         channelId,
         body: t('chat.shared_location'),
         messageType: ChatMessageType.Location,
-        metadataJson: JSON.stringify({ Latitude: latitude, Longitude: longitude }),
+        metadataJson: buildLocationMetadata(latitude, longitude),
         threadRootMessageId: messageId,
         priority: urgent ? ChatMessagePriority.Urgent : ChatMessagePriority.Normal,
       });
@@ -129,13 +126,17 @@ export default function ThreadScreen() {
 
         <FlatList
           data={replies}
-          maintainVisibleContentPosition={{ startRenderingFromBottom: true }}
+          // autoscrollToBottomThreshold is off by default in FlashList v2; without it a
+          // new reply lands below the viewport, hidden behind the composer.
+          maintainVisibleContentPosition={{ startRenderingFromBottom: true, autoscrollToBottomThreshold: 0.2 }}
           keyExtractor={(item: ChatMessageResultData) => item.ChatMessageId}
           renderItem={renderItem}
           contentContainerStyle={{ paddingVertical: 8 }}
         />
 
-        <MessageComposer onSendText={handleSendText} onSendImage={() => undefined} onSendLocation={handleSendLocation} onOpenGif={handleSendGif} onTyping={() => undefined} placeholder={t('chat.reply_placeholder')} allowUrgent={false} />
+        {/* Threads carry text and location only; omitting the image/GIF callbacks keeps
+            those actions out of the composer instead of showing dead buttons. */}
+        <MessageComposer onSendText={handleSendText} onSendLocation={handleSendLocation} onTyping={() => undefined} placeholder={t('chat.reply_placeholder')} allowUrgent={false} />
       </KeyboardAvoidingView>
     </Box>
   );
diff --git a/src/components/chat/__tests__/message-composer.test.tsx b/src/components/chat/__tests__/message-composer.test.tsx
new file mode 100644
index 00000000..4c983919
--- /dev/null
+++ b/src/components/chat/__tests__/message-composer.test.tsx
@@ -0,0 +1,93 @@
+/**
+ * The composer toolbar must only offer actions the host surface can actually perform.
+ * Thread replies send text and location only; when they still rendered the image button
+ * the picker opened and the chosen photo was silently dropped.
+ */
+import { fireEvent, render, screen } from '@testing-library/react-native';
+import React from 'react';
+
+jest.mock('expo-image-picker', () => ({
+  requestMediaLibraryPermissionsAsync: jest.fn().mockResolvedValue({ granted: true }),
+  launchImageLibraryAsync: jest.fn().mockResolvedValue({ canceled: true, assets: [] }),
+}));
+
+jest.mock('expo-location', () => ({
+  requestForegroundPermissionsAsync: jest.fn().mockResolvedValue({ granted: true }),
+  getCurrentPositionAsync: jest.fn().mockResolvedValue({ coords: { latitude: 0, longitude: 0 } }),
+}));
+
+jest.mock('@/lib/logging', () => ({
+  logger: { info: jest.fn(), error: jest.fn(), warn: jest.fn(), debug: jest.fn(), trace: jest.fn(), fatal: jest.fn() },
+}));
+
+jest.mock('@/stores/toast/store', () => ({
+  useToastStore: { getState: () => ({ showToast: jest.fn() }) },
+}));
+
+jest.mock('react-i18next', () => ({
+  useTranslation: () => ({ t: (key: string) => key }),
+}));
+
+// The shared lucide mock only exports the icons other suites use; this composer pulls in
+// several it does not, which would otherwise render as undefined elements.
+jest.mock('lucide-react-native', () => {
+  const React = require('react');
+  const { View } = require('react-native');
+  const icon = React.forwardRef((props: Record<string, unknown>, ref: unknown) => React.createElement(View, { ...props, ref }));
+  return new Proxy({}, { get: () => icon });
+});
+
+import { MessageComposer } from '../message-composer';
+
+const baseProps = {
+  onSendText: jest.fn(),
+  onSendLocation: jest.fn(),
+  onTyping: jest.fn(),
+};
+
+describe('MessageComposer attachment actions', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('offers image and GIF when both callbacks are provided', () => {
+    render(<MessageComposer {...baseProps} onSendImage={jest.fn()} onOpenGif={jest.fn()} />);
+
+    expect(screen.queryByLabelText('chat.add_image')).not.toBeNull();
+    expect(screen.queryByLabelText('chat.add_gif')).not.toBeNull();
+    expect(screen.queryByLabelText('chat.emoji')).not.toBeNull();
+  });
+
+  it('hides both when neither callback is provided, as thread replies do', () => {
+    render(<MessageComposer {...baseProps} allowUrgent={false} />);
+
+    expect(screen.queryByLabelText('chat.add_image')).toBeNull();
+    expect(screen.queryByLabelText('chat.add_gif')).toBeNull();
+    // The actions a thread can still perform stay available.
+    expect(screen.queryByLabelText('chat.emoji')).not.toBeNull();
+    expect(screen.queryByLabelText('chat.share_location')).not.toBeNull();
+  });
+
+  it('hides only the GIF action when images are supported but GIFs are not', () => {
+    render(<MessageComposer {...baseProps} onSendImage={jest.fn()} />);
+
+    expect(screen.queryByLabelText('chat.add_image')).not.toBeNull();
+    expect(screen.queryByLabelText('chat.add_gif')).toBeNull();
+  });
+
+  it('hides only the image action when GIFs are supported but images are not', () => {
+    render(<MessageComposer {...baseProps} onOpenGif={jest.fn()} />);
+
+    expect(screen.queryByLabelText('chat.add_image')).toBeNull();
+    expect(screen.queryByLabelText('chat.add_gif')).not.toBeNull();
+  });
+
+  it('invokes the GIF callback when the action is used', () => {
+    const onOpenGif = jest.fn();
+    render(<MessageComposer {...baseProps} onOpenGif={onOpenGif} />);
+
+    fireEvent.press(screen.getByLabelText('chat.add_gif'));
+
+    expect(onOpenGif).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/components/chat/chat-utils.ts b/src/components/chat/chat-utils.ts
index ac547514..3d0476b0 100644
--- a/src/components/chat/chat-utils.ts
+++ b/src/components/chat/chat-utils.ts
@@ -64,12 +64,55 @@ export function parseMetadata<T>(metadataJson?: string | null): T | null {
   }
 }
 
+/**
+ * MetadataJson wire contract, shared with the web client: a nested, camelCase envelope
+ * — `{ location: { latitude, longitude, label } }` and `{ gif: { url, previewUrl, width,
+ * height } }`. Earlier mobile builds wrote a flat PascalCase object that the web client
+ * cannot read (it falls back to rendering the message body), so the builders below emit
+ * only the nested form while the parsers still accept the flat one for history already
+ * stored on the server.
+ */
+function readString(value: unknown): string | undefined {
+  return typeof value === 'string' && value.length > 0 ? value : undefined;
+}
+
+function readNumber(value: unknown): number | undefined {
+  return typeof value === 'number' && Number.isFinite(value) ? value : undefined;
+}
+
+export function buildLocationMetadata(latitude: number, longitude: number, label?: string): string {
+  return JSON.stringify({ location: { latitude, longitude, label } });
+}
+
+export function buildGifMetadata(gif: { GifUrl: string; PreviewUrl?: string; Width?: number; Height?: number }): string {
+  return JSON.stringify({ gif: { url: gif.GifUrl, previewUrl: gif.PreviewUrl, width: gif.Width, height: gif.Height } });
+}
+
 export function parseLocationMetadata(metadataJson?: string | null): ChatLocationMetadata | null {
-  return parseMetadata<ChatLocationMetadata>(metadataJson);
+  const raw = parseMetadata<Record<string, unknown>>(metadataJson);
+  if (!raw) return null;
+  const nested = (raw.location ?? raw.Location) as Record<string, unknown> | undefined;
+  const source = nested ?? raw;
+  const latitude = readNumber(source.latitude ?? source.Latitude);
+  const longitude = readNumber(source.longitude ?? source.Longitude);
+  if (latitude === undefined || longitude === undefined) return null;
+  return { Latitude: latitude, Longitude: longitude, Label: readString(source.label ?? source.Label) };
 }
 
 export function parseGifMetadata(metadataJson?: string | null): ChatGifMetadata | null {
-  return parseMetadata<ChatGifMetadata>(metadataJson);
+  const raw = parseMetadata<Record<string, unknown>>(metadataJson);
+  if (!raw) return null;
+  const nested = (raw.gif ?? raw.Gif) as Record<string, unknown> | undefined;
+  const source = nested ?? raw;
+  const url = readString(source.url ?? source.Url ?? source.gifUrl ?? source.GifUrl);
+  if (!url) return null;
+  return {
+    GifUrl: url,
+    PreviewUrl: readString(source.previewUrl ?? source.PreviewUrl),
+    Width: readNumber(source.width ?? source.Width),
+    Height: readNumber(source.height ?? source.Height),
+    Title: readString(source.title ?? source.Title),
+  };
 }
 
 export function parseImageMetadata(metadataJson?: string | null): ChatImageMetadata | null {
diff --git a/src/components/chat/message-actions-sheet.tsx b/src/components/chat/message-actions-sheet.tsx
index 1bc66c2f..c6ee3171 100644
--- a/src/components/chat/message-actions-sheet.tsx
+++ b/src/components/chat/message-actions-sheet.tsx
@@ -16,7 +16,7 @@ interface MessageActionsSheetProps {
   onClose: () => void;
   isOwn: boolean;
   isModerator: boolean;
-  /** Assistant conversations: no reactions, threads or deletes — copy, edit own, pin and flag stay. */
+  /** Assistant conversations: no reactions, threads, deletes or edits — copy, pin and flag stay. */
   assistant?: boolean;
   onReact: (message: ChatMessageResultData, emoji: string) => void;
   onReply: (message: ChatMessageResultData) => void;
@@ -118,7 +118,7 @@ export function MessageActionsSheet({ message, isOpen, onClose, isOwn, isModerat
               </ActionsheetItem>
             ) : null}
 
-            {isOwn && isText && !isDeleted ? (
+            {isOwn && isText && !isDeleted && !assistant ? (
               <ActionsheetItem
                 onPress={() => {
                   onEdit(message);
diff --git a/src/components/chat/message-bubble.tsx b/src/components/chat/message-bubble.tsx
index fc92b09a..1bdf0569 100644
--- a/src/components/chat/message-bubble.tsx
+++ b/src/components/chat/message-bubble.tsx
@@ -5,7 +5,7 @@ import { useTranslation } from 'react-i18next';
 import { Linking } from 'react-native';
 
 import { getChatAttachmentImageSource } from '@/api/chat/chat';
-import { Avatar, AvatarFallbackText, AvatarImage } from '@/components/ui/avatar';
+import { Avatar, AvatarImage } from '@/components/ui/avatar';
 import { Box } from '@/components/ui/box';
 import { HStack } from '@/components/ui/hstack';
 import { Pressable } from '@/components/ui/pressable';
@@ -30,9 +30,11 @@ interface MessageBubbleProps {
 export function MessageBubble({ message, isOwn, showSender, currentUserId, onLongPress, onToggleReaction, onOpenThread, onRetry, onPressImage }: MessageBubbleProps) {
   const { t } = useTranslation();
 
+  // Realtime payloads omit empty collections; the store normalizes them, but messages
+  // persisted before that normalization existed can still come back without them.
   const groupedReactions = useMemo(() => {
     const map = new Map<string, { count: number; mine: boolean }>();
-    for (const reaction of message.Reactions) {
+    for (const reaction of message.Reactions ?? []) {
       const current = map.get(reaction.Emoji) ?? { count: 0, mine: false };
       current.count += 1;
       if (reaction.UserId && reaction.UserId === currentUserId) current.mine = true;
@@ -65,7 +67,7 @@ export function MessageBubble({ message, isOwn, showSender, currentUserId, onLon
     }
 
     if (message.MessageType === ChatMessageType.Image) {
-      const attachment = message.Attachments[0];
+      const attachment = (message.Attachments ?? [])[0];
       const uri = message._localAttachmentUri ?? (attachment ? getChatAttachmentImageSource(attachment.ChatAttachmentId).uri : undefined);
       const source = attachment ? getChatAttachmentImageSource(attachment.ChatAttachmentId) : uri ? { uri } : undefined;
       if (!source) return <Text className={textTone}>{message.Body}</Text>;
@@ -121,14 +123,9 @@ export function MessageBubble({ message, isOwn, showSender, currentUserId, onLon
 
   return (
     <HStack className={`my-1 px-3 ${isOwn ? 'justify-end' : 'justify-start'}`} space="sm">
-      {!isOwn && showSender ? (
-        <Avatar size="sm">
-          <AvatarFallbackText>{message.SenderDisplayName ?? '?'}</AvatarFallbackText>
-          {message.SenderUserId ? <AvatarImage source={{ uri: getPersonAvatarUrl(message.SenderUserId) ?? '' }} /> : null}
-        </Avatar>
-      ) : !isOwn ? (
-        <Box className="w-8" />
-      ) : null}
+      {/* No initials fallback: the avatar endpoint always answers with a silhouette
+          placeholder rather than a 404, so initials would never be visible anyway. */}
+      {!isOwn && showSender ? <Avatar size="sm">{message.SenderUserId ? <AvatarImage source={{ uri: getPersonAvatarUrl(message.SenderUserId) ?? '' }} /> : null}</Avatar> : !isOwn ? <Box className="w-8" /> : null}
 
       <VStack className={`max-w-[78%] ${isOwn ? 'items-end' : 'items-start'}`} space="xs">
         {!isOwn && showSender && message.SenderDisplayName ? <Text className="ml-1 text-xs font-medium text-typography-500">{message.SenderDisplayName}</Text> : null}
diff --git a/src/components/chat/message-composer.tsx b/src/components/chat/message-composer.tsx
index 45a4f142..51ad4c81 100644
--- a/src/components/chat/message-composer.tsx
+++ b/src/components/chat/message-composer.tsx
@@ -19,9 +19,12 @@ const TYPING_IDLE_MS = 3000;
 
 interface MessageComposerProps {
   onSendText: (body: string, urgent: boolean) => void;
-  onSendImage: (uri: string, urgent: boolean, mimeType?: string) => void;
+  /** Omit to hide the image action; a surface that cannot send images (thread replies)
+   * would otherwise open the picker and silently discard the chosen photo. */
+  onSendImage?: (uri: string, urgent: boolean, mimeType?: string) => void;
   onSendLocation: (latitude: number, longitude: number, urgent: boolean) => void;
-  onOpenGif: () => void;
+  /** Omit to hide the GIF action on surfaces that cannot send GIFs. */
+  onOpenGif?: () => void;
   onTyping: (isTyping: boolean) => void;
   disabled?: boolean;
   placeholder?: string;
@@ -81,6 +84,7 @@ export function MessageComposer({ onSendText, onSendImage, onSendLocation, onOpe
   }, [text, urgent, onSendText, stopTyping]);
 
   const handlePickImage = useCallback(async () => {
+    if (!onSendImage) return;
     try {
       const permission = await ImagePicker.requestMediaLibraryPermissionsAsync();
       if (!permission.granted) {
@@ -125,12 +129,16 @@ export function MessageComposer({ onSendText, onSendImage, onSendLocation, onOpe
           </Textarea>
         </Box>
 
-        <Pressable className="p-2" onPress={handlePickImage} disabled={disabled} accessibilityLabel={t('chat.add_image')}>
-          <ImagePlus size={22} color="#6b7280" />
-        </Pressable>
-        <Pressable className="p-2" onPress={onOpenGif} disabled={disabled} accessibilityLabel={t('chat.add_gif')}>
-          <Sparkles size={22} color="#6b7280" />
-        </Pressable>
+        {onSendImage ? (
+          <Pressable className="p-2" onPress={handlePickImage} disabled={disabled} accessibilityLabel={t('chat.add_image')}>
+            <ImagePlus size={22} color="#6b7280" />
+          </Pressable>
+        ) : null}
+        {onOpenGif ? (
+          <Pressable className="p-2" onPress={onOpenGif} disabled={disabled} accessibilityLabel={t('chat.add_gif')}>
+            <Sparkles size={22} color="#6b7280" />
+          </Pressable>
+        ) : null}
         <Pressable className="p-2" onPress={handleShareLocation} disabled={disabled} accessibilityLabel={t('chat.share_location')}>
           <MapPin size={22} color="#6b7280" />
         </Pressable>
diff --git a/src/components/chat/new-conversation-sheet.tsx b/src/components/chat/new-conversation-sheet.tsx
index 100ef30e..7365d6de 100644
--- a/src/components/chat/new-conversation-sheet.tsx
+++ b/src/components/chat/new-conversation-sheet.tsx
@@ -5,7 +5,7 @@ import { useTranslation } from 'react-i18next';
 import { createAdHocChannel, createDirectMessage } from '@/api/chat/chat';
 import { getRecipients } from '@/api/messaging/messages';
 import { Actionsheet, ActionsheetBackdrop, ActionsheetContent, ActionsheetDragIndicator, ActionsheetDragIndicatorWrapper } from '@/components/ui/actionsheet';
-import { Avatar, AvatarFallbackText, AvatarImage } from '@/components/ui/avatar';
+import { Avatar, AvatarImage } from '@/components/ui/avatar';
 import { Box } from '@/components/ui/box';
 import { Button, ButtonText } from '@/components/ui/button';
 import { Center } from '@/components/ui/center';
@@ -172,7 +172,6 @@ export function NewConversationSheet({ isOpen, onClose, mode, onCreated }: NewCo
                     <HStack className="items-center justify-between">
                       <HStack className="flex-1 items-center" space="sm">
                         <Avatar size="sm">
-                          <AvatarFallbackText>{recipient.Name}</AvatarFallbackText>
                           <AvatarImage source={{ uri: getAvatarUrl(userId) }} />
                         </Avatar>
                         <Text className="flex-1 text-typography-900" numberOfLines={1}>
diff --git a/src/services/signalr.service.ts b/src/services/signalr.service.ts
index 5fdda979..0d782a49 100644
--- a/src/services/signalr.service.ts
+++ b/src/services/signalr.service.ts
@@ -22,6 +22,9 @@ export interface SignalRMessage {
   data: unknown;
 }
 
+/** Hub events can carry multiple positional arguments; listeners receive all of them. */
+export type SignalREventListener = (...data: unknown[]) => void;
+
 export enum HubConnectingState {
   IDLE = 'idle',
   RECONNECTING = 'reconnecting',
@@ -245,12 +248,12 @@ class SignalRService {
           context: { method },
         });
 
-        connection.on(method, (data) => {
+        connection.on(method, (...args: unknown[]) => {
           logger.debug({
             message: `Received ${method} message from hub: ${config.name}`,
-            context: { method, data },
+            context: { method, args },
           });
-          this.handleMessage(config.name, method, data);
+          this.handleMessage(config.name, method, args);
         });
       });
 
@@ -383,12 +386,12 @@ class SignalRService {
           context: { method },
         });
 
-        connection.on(method, (data) => {
+        connection.on(method, (...args: unknown[]) => {
           logger.debug({
             message: `Received ${method} message from hub: ${config.name}`,
-            context: { method, data },
+            context: { method, args },
           });
-          this.handleMessage(config.name, method, data);
+          this.handleMessage(config.name, method, args);
         });
       });
 
@@ -535,9 +538,11 @@ class SignalRService {
     this.reconnectTimers.set(hubName, reconnectTimer);
   }
 
-  private handleMessage(_hubName: string, method: string, data: unknown): void {
-    // Emit event for subscribers using the method name as the event name
-    this.emit(method, data);
+  private handleMessage(_hubName: string, method: string, args: unknown[]): void {
+    // Emit event for subscribers using the method name as the event name. Hub methods
+    // can send more than one argument (chatPresenceChanged sends `userId, isOnline`),
+    // so forward every argument to the listeners.
+    this.emit(method, ...args);
   }
 
   public async disconnectFromHub(hubName: string): Promise<void> {
@@ -645,16 +650,16 @@ class SignalRService {
   }
 
   // Event emitter methods
-  private eventListeners: Map<string, Set<(data: unknown) => void>> = new Map();
+  private eventListeners: Map<string, Set<SignalREventListener>> = new Map();
 
-  public on(event: string, callback: (data: unknown) => void): void {
+  public on(event: string, callback: SignalREventListener): void {
     if (!this.eventListeners.has(event)) {
       this.eventListeners.set(event, new Set());
     }
     this.eventListeners.get(event)?.add(callback);
   }
 
-  public off(event: string, callback: (data: unknown) => void): void {
+  public off(event: string, callback: SignalREventListener): void {
     this.eventListeners.get(event)?.delete(callback);
   }
 
@@ -662,12 +667,12 @@ class SignalRService {
     this.eventListeners.delete(event);
   }
 
-  private emit(event: string, data: unknown): void {
+  private emit(event: string, ...data: unknown[]): void {
     // Isolate listener failures — one throwing callback must not prevent the
     // remaining listeners from receiving the event.
     this.eventListeners.get(event)?.forEach((callback) => {
       try {
-        callback(data);
+        callback(...data);
       } catch (error) {
         logger.error({
           message: `SignalR event listener threw for event: ${event}`,
diff --git a/src/stores/chat/__tests__/hub-invoke-args.test.ts b/src/stores/chat/__tests__/hub-invoke-args.test.ts
new file mode 100644
index 00000000..02fc3f53
--- /dev/null
+++ b/src/stores/chat/__tests__/hub-invoke-args.test.ts
@@ -0,0 +1,176 @@
+/**
+ * SignalR binds hub arguments positionally and rejects an invocation that supplies
+ * fewer arguments than the hub method declares — C# default values do not make a
+ * parameter optional on the wire. These tests pin the argument counts against the
+ * ChatHub signatures so a short invoke can never silently strand the client outside
+ * its channel groups again:
+ *
+ *   JoinChannel(string channelId, int? asUnitId)
+ *   Typing(string channelId, string displayName, bool isTyping, int? asUnitId)
+ *   MarkRead(string channelId, long seq, int? asUnitId)
+ */
+const mockInvoke = jest.fn().mockResolvedValue(undefined);
+
+jest.mock('@/services/signalr.service', () => ({
+  signalRService: { invoke: mockInvoke },
+}));
+
+jest.mock('@/lib/env', () => ({
+  Env: { CHAT_HUB_NAME: 'chatHub' },
+}));
+
+jest.mock('@/lib/logging', () => ({
+  logger: { info: jest.fn(), error: jest.fn(), warn: jest.fn(), debug: jest.fn(), trace: jest.fn(), fatal: jest.fn() },
+}));
+
+jest.mock('@/lib/i18n/utils', () => ({ translate: (key: string) => key }));
+
+jest.mock('@/lib/storage', () => ({ zustandStorage: { getItem: jest.fn(), setItem: jest.fn(), removeItem: jest.fn() } }));
+
+jest.mock('@/api/chat/chat', () => ({
+  getChannels: jest.fn().mockResolvedValue({ Data: [] }),
+  getMessages: jest.fn().mockResolvedValue({ Data: [] }),
+  getMembers: jest.fn().mockResolvedValue({ Data: [] }),
+  getMyPendingAcks: jest.fn().mockResolvedValue({ Data: [] }),
+  markRead: jest.fn().mockResolvedValue(undefined),
+}));
+
+jest.mock('@/api/chat/chatbot', () => ({
+  getChatbotChannel: jest.fn(),
+  sendChatbotMessage: jest.fn(),
+  newChatbotSession: jest.fn(),
+}));
+
+jest.mock('@/stores/auth/store', () => ({
+  __esModule: true,
+  default: { getState: () => ({ userId: 'user-1', profile: { name: 'Test User' } }) },
+}));
+
+jest.mock('@/stores/toast/store', () => ({
+  useToastStore: { getState: () => ({ showToast: jest.fn() }) },
+}));
+
+jest.mock('@/stores/app/core-store', () => ({
+  useCoreStore: { getState: () => ({ activeUnitId: '42', activeUnit: { Name: 'Engine 6' } }) },
+}));
+
+// Loaded lazily so the mock factories above run after their `mock*` consts exist.
+type ChatStoreApi = typeof import('../store').useChatStore;
+let useChatStore: ChatStoreApi;
+
+beforeAll(() => {
+  useChatStore = require('../store').useChatStore as ChatStoreApi;
+});
+
+describe('chat hub invocations', () => {
+  beforeEach(() => {
+    mockInvoke.mockClear();
+    mockInvoke.mockResolvedValue(undefined);
+    useChatStore.setState({ messagesByChannel: {}, channels: [] });
+  });
+
+  it('sends both JoinChannel arguments', async () => {
+    await useChatStore.getState().joinChannel('channel-1');
+
+    expect(mockInvoke).toHaveBeenCalledWith('chatHub', 'JoinChannel', 'channel-1', 42);
+  });
+
+  it('sends all four Typing arguments in hub order', () => {
+    useChatStore.getState().sendTyping('channel-1', true);
+
+    expect(mockInvoke).toHaveBeenCalledWith('chatHub', 'Typing', 'channel-1', 'Engine 6', true, 42);
+  });
+
+  it('sends all three MarkRead arguments', async () => {
+    useChatStore.setState({
+      messagesByChannel: {
+        'channel-1': [
+          {
+            ChatMessageId: 'm1',
+            ChatChannelId: 'channel-1',
+            MessageSeq: 42,
+            SenderParticipantType: 0,
+            SenderUserId: 'user-2',
+            SenderDisplayName: 'Other',
+            Body: 'hi',
+            MessageType: 0,
+            Priority: 0,
+            ThreadRootMessageId: null,
+            ThreadReplyCount: 0,
+            AlsoSendToChannel: false,
+            MetadataJson: null,
+            ClientMessageId: 'c1',
+            SentOn: new Date(0).toISOString(),
+            Reactions: [],
+            Attachments: [],
+          },
+        ],
+      },
+    } as unknown as Parameters<typeof useChatStore.setState>[0]);
+
+    await useChatStore.getState().markChannelRead('channel-1');
+
+    expect(mockInvoke).toHaveBeenCalledWith('chatHub', 'MarkRead', 'channel-1', 42, 42);
+  });
+});
+
+describe('incoming message normalization', () => {
+  beforeEach(() => {
+    useChatStore.setState({ messagesByChannel: {}, channels: [] });
+  });
+
+  it('fills in collections the hub payload omits', () => {
+    // The hub sends the message DTO as a JSON string and drops empty collections.
+    useChatStore.getState().handleMessageReceived(JSON.stringify({ ChatMessageId: 'm1', ChatChannelId: 'channel-1', MessageSeq: 10, Body: 'hi', SentOn: new Date(0).toISOString() }));
+
+    const stored = useChatStore.getState().messagesByChannel['channel-1']?.[0];
+    expect(stored?.Reactions).toEqual([]);
+    expect(stored?.Attachments).toEqual([]);
+  });
+
+  it('keeps existing reactions when a later payload omits them', () => {
+    useChatStore.getState().handleMessageReceived({ ChatMessageId: 'm1', ChatChannelId: 'channel-1', MessageSeq: 10, Body: 'hi', SentOn: new Date(0).toISOString(), Reactions: [{ Emoji: '\u{1F44D}', UserId: 'user-2' }] });
+    useChatStore.getState().handleMessageEdited({ ChatMessageId: 'm1', ChatChannelId: 'channel-1', MessageSeq: 10, Body: 'hi (edited)', SentOn: new Date(0).toISOString() });
+
+    const stored = useChatStore.getState().messagesByChannel['channel-1']?.[0];
+    expect(stored?.Body).toBe('hi (edited)');
+    expect(stored?.Reactions).toHaveLength(1);
+  });
+});
+
+describe('chat presence events', () => {
+  beforeEach(() => {
+    useChatStore.setState({ presence: new Set<string>() });
+  });
+
+  it('accepts the hub positional (userId, isOnline) form', () => {
+    useChatStore.getState().handlePresenceChanged('user-2', true);
+    expect(useChatStore.getState().presence.has('user-2')).toBe(true);
+
+    useChatStore.getState().handlePresenceChanged('user-2', false);
+    expect(useChatStore.getState().presence.has('user-2')).toBe(false);
+  });
+
+  it('still accepts an object payload', () => {
+    useChatStore.getState().handlePresenceChanged({ UserId: 'user-3', IsOnline: true });
+    expect(useChatStore.getState().presence.has('user-3')).toBe(true);
+  });
+});
+
+describe('chat typing events', () => {
+  beforeEach(() => {
+    useChatStore.setState({ typingByChannel: {} });
+  });
+
+  it('reads the hub payload ChannelId field', () => {
+    useChatStore.getState().handleTyping({ ChannelId: 'channel-1', UserId: 'user-2', DisplayName: 'Other', IsTyping: true });
+
+    expect(useChatStore.getState().typingByChannel['channel-1']?.[0]?.displayName).toBe('Other');
+  });
+
+  it('reads a camelCase hub payload', () => {
+    useChatStore.getState().handleTyping({ channelId: 'channel-1', userId: 'user-2', displayName: 'Other', isTyping: true });
+
+    expect(useChatStore.getState().typingByChannel['channel-1']?.[0]?.userId).toBe('user-2');
+  });
+});
diff --git a/src/stores/chat/store.ts b/src/stores/chat/store.ts
index dbbb2b32..a2cd3934 100644
--- a/src/stores/chat/store.ts
+++ b/src/stores/chat/store.ts
@@ -120,7 +120,7 @@ interface ChatState {
   handleChatbotMessageReceived: (raw: unknown) => void;
   handleChatbotTyping: (raw: unknown) => void;
   handleTyping: (raw: unknown) => void;
-  handlePresenceChanged: (raw: unknown) => void;
+  handlePresenceChanged: (raw: unknown, isOnlineArg?: unknown) => void;
   handleChatConnected: () => void;
 
   reset: () => void;
@@ -159,6 +159,16 @@ function activeUnitIdNumber(): number | undefined {
   return Number.isFinite(parsed) ? parsed : undefined;
 }
 
+/**
+ * Name broadcast with typing signals; the hub echoes it to the other participants.
+ * The active unit is this app's chat identity, so it wins over the signed-in user.
+ */
+function currentDisplayName(): string | null {
+  const unitName = useCoreStore.getState().activeUnit?.Name;
+  if (unitName) return unitName;
+  return useAuthStore.getState().profile?.name ?? null;
+}
+
 function parseEventData<T>(raw: unknown): T | null {
   if (raw == null) return null;
   if (typeof raw === 'string') {
@@ -182,6 +192,18 @@ function compareMessages(a: ChatMessageResultData, b: ChatMessageResultData): nu
   return new Date(a.SentOn).getTime() - new Date(b.SentOn).getTime();
 }
 
+/** The realtime payloads omit empty collections even though the DTO types them as
+ * required, so every stored message is normalized on the way in — the UI iterates
+ * Reactions/Attachments directly. An existing value always wins over a missing one
+ * so a partial hub update can never drop reactions already on screen. */
+function withCollections(incoming: ChatMessageResultData, existing?: ChatMessageResultData): ChatMessageResultData {
+  return {
+    ...incoming,
+    Reactions: incoming.Reactions ?? existing?.Reactions ?? [],
+    Attachments: incoming.Attachments ?? existing?.Attachments ?? [],
+  };
+}
+
 /** Insert or replace a message in an ascending-by-sequence list, de-duplicated
  * by ChatMessageId and ClientMessageId (so optimistic sends reconcile). */
 function upsertMessage(list: ChatMessageResultData[], incoming: ChatMessageResultData): ChatMessageResultData[] {
@@ -189,9 +211,9 @@ function upsertMessage(list: ChatMessageResultData[], incoming: ChatMessageResul
   const idx = next.findIndex((m) => m.ChatMessageId === incoming.ChatMessageId || (!!incoming.ClientMessageId && !!m.ClientMessageId && m.ClientMessageId === incoming.ClientMessageId));
   if (idx >= 0) {
     const existing = next[idx];
-    next[idx] = { ...existing, ...incoming };
+    next[idx] = withCollections({ ...existing, ...incoming }, existing);
   } else {
-    next.push(incoming);
+    next.push(withCollections(incoming));
   }
   next.sort(compareMessages);
   return next;
@@ -547,7 +569,10 @@ export const useChatStore = create<ChatState>()(
 
         // Read pointer is recorded against the active unit identity in the Unit app.
         const asUnitId = activeUnitIdNumber();
-        void safeInvoke('MarkRead', channelId, seq, ...(asUnitId != null ? [asUnitId] : []));
+        // Hub signature: MarkRead(channelId, seq, asUnitId). SignalR binds hub arguments
+        // positionally and rejects an invocation that supplies fewer than the method
+        // declares, so asUnitId is always sent — null when there is no active unit.
+        void safeInvoke('MarkRead', channelId, seq, asUnitId ?? null);
         try {
           await chatApi.markRead(channelId, { Seq: seq, AsUnitId: asUnitId });
         } catch (error) {
@@ -664,7 +689,10 @@ export const useChatStore = create<ChatState>()(
       joinChannel: async (channelId: string) => {
         // Join as the active unit so hub-side membership resolves to the unit.
         const asUnitId = activeUnitIdNumber();
-        await safeInvoke('JoinChannel', channelId, ...(asUnitId != null ? [asUnitId] : []));
+        // Hub signature: JoinChannel(channelId, asUnitId). Omitting the optional argument
+        // makes SignalR reject the invocation, which leaves the connection outside the
+        // channel group and the channel permanently silent.
+        await safeInvoke('JoinChannel', channelId, asUnitId ?? null);
       },
 
       sendTyping: (channelId: string, isTyping: boolean) => {
@@ -677,7 +705,10 @@ export const useChatStore = create<ChatState>()(
           lastTypingSentAt.delete(channelId);
         }
         const asUnitId = activeUnitIdNumber();
-        void safeInvoke('Typing', channelId, isTyping, ...(asUnitId != null ? [asUnitId] : []));
+        // Hub signature: Typing(channelId, displayName, isTyping, asUnitId). The previous
+        // call put isTyping in the displayName slot and dropped two arguments, so the hub
+        // rejected every typing signal.
+        void safeInvoke('Typing', channelId, currentDisplayName(), isTyping, asUnitId ?? null);
       },
 
       // ------------------------------------------------------------------
@@ -782,8 +813,10 @@ export const useChatStore = create<ChatState>()(
       },
 
       handleTyping: (raw: unknown) => {
-        const obj = (typeof raw === 'object' && raw !== null ? (raw as Record<string, unknown>) : {}) as Record<string, unknown>;
-        const channelId = (obj.ChatChannelId ?? obj.chatChannelId ?? obj.ChannelId) as string | undefined;
+        // The hub payload uses ChannelId (not ChatChannelId) and its casing depends on the
+        // server's JSON naming policy, so accept both spellings of every field.
+        const obj = (parseEventData<Record<string, unknown>>(raw) ?? {}) as Record<string, unknown>;
+        const channelId = (obj.ChatChannelId ?? obj.chatChannelId ?? obj.ChannelId ?? obj.channelId) as string | undefined;
         const userId = (obj.UserId ?? obj.userId) as string | undefined;
         const displayName = (obj.DisplayName ?? obj.displayName) as string | undefined;
         const isTyping = (obj.IsTyping ?? obj.isTyping) as boolean | undefined;
@@ -797,10 +830,12 @@ export const useChatStore = create<ChatState>()(
         addTyping(set, channelId, { userId, displayName, expiresAt: Date.now() + TYPING_EXPIRY_MS });
       },
 
-      handlePresenceChanged: (raw: unknown) => {
+      handlePresenceChanged: (raw: unknown, isOnlineArg?: unknown) => {
+        // The hub sends `chatPresenceChanged` as two positional args (userId, isOnline);
+        // keep the object form working in case a future producer sends a DTO.
         const obj = (typeof raw === 'object' && raw !== null ? (raw as Record<string, unknown>) : {}) as Record<string, unknown>;
-        const userId = (obj.UserId ?? obj.userId) as string | undefined;
-        const isOnline = (obj.IsOnline ?? obj.isOnline) as boolean | undefined;
+        const userId = typeof raw === 'string' ? raw : ((obj.UserId ?? obj.userId) as string | undefined);
+        const isOnline = typeof raw === 'string' ? Boolean(isOnlineArg) : ((obj.IsOnline ?? obj.isOnline) as boolean | undefined);
         if (!userId) return;
         set((s) => {
           const presence = new Set(s.presence);
diff --git a/src/stores/signalr/signalr-store.ts b/src/stores/signalr/signalr-store.ts
index f4fca1d4..ee82227b 100644
--- a/src/stores/signalr/signalr-store.ts
+++ b/src/stores/signalr/signalr-store.ts
@@ -31,9 +31,30 @@ const CHAT_HUB_METHODS = [
 ];
 
 // Track registered chat handlers for cleanup and the heartbeat timer.
-const chatHubHandlers: Record<string, ((data: unknown) => void) | null> = {};
+// Hub methods can send several positional arguments, so handlers are variadic.
+const chatHubHandlers: Record<string, ((...args: unknown[]) => void) | null> = {};
 let chatHeartbeatTimer: ReturnType<typeof setInterval> | null = null;
 const CHAT_HEARTBEAT_INTERVAL_MS = 45000;
+const CHAT_ARM_RETRY_MS = 5000;
+const CHAT_ARM_MAX_ATTEMPTS = 3;
+// The hub replays a full resync on arm; collapse the duplicate that arrives when the
+// server echoes its own onChatConnected right after ours. Scoped to a single connection —
+// a disconnect clears the marker so the next one resyncs immediately.
+const CHAT_RESYNC_DEBOUNCE_MS = 2000;
+
+let chatArmRetryTimer: ReturnType<typeof setTimeout> | null = null;
+let chatArmAttempts = 0;
+// The arm in flight, shared by the reconnect handler and the connectChatHub fallback so a
+// fresh connection announces itself exactly once.
+let chatArmOperation: Promise<void> | null = null;
+let lastChatResyncAt = 0;
+
+function stopChatArmRetry(): void {
+  if (chatArmRetryTimer) {
+    clearTimeout(chatArmRetryTimer);
+    chatArmRetryTimer = null;
+  }
+}
 
 function unregisterChatHubHandlers(): void {
   Object.keys(chatHubHandlers).forEach((event) => {
@@ -52,6 +73,77 @@ function stopChatHeartbeat(): void {
   }
 }
 
+function resyncChat(): void {
+  const now = Date.now();
+  if (now - lastChatResyncAt < CHAT_RESYNC_DEBOUNCE_MS) return;
+  lastChatResyncAt = now;
+  useChatStore.getState().handleChatConnected();
+}
+
+/**
+ * Announce this connection to the chat hub and restart the heartbeat.
+ *
+ * The hub only places a connection into its channel groups in response to `Connect`, and
+ * every reconnect issues a fresh connection id. Without re-arming, the websocket stays
+ * open but the client receives nothing.
+ */
+async function runChatArm(): Promise<void> {
+  stopChatArmRetry();
+
+  try {
+    await signalRService.invoke(Env.CHAT_HUB_NAME, 'Connect');
+  } catch (error) {
+    chatArmAttempts += 1;
+    logger.warn({
+      message: 'Failed to announce presence to chat hub',
+      context: { error, attempt: chatArmAttempts, maxAttempts: CHAT_ARM_MAX_ATTEMPTS },
+    });
+    if (chatArmAttempts < CHAT_ARM_MAX_ATTEMPTS) {
+      chatArmRetryTimer = setTimeout(() => {
+        void armChatSession();
+      }, CHAT_ARM_RETRY_MS);
+    }
+    throw error;
+  }
+
+  chatArmAttempts = 0;
+
+  stopChatHeartbeat();
+  chatHeartbeatTimer = setInterval(() => {
+    signalRService.invoke(Env.CHAT_HUB_NAME, 'Heartbeat').catch(() => {
+      // Heartbeat is best-effort; ignore transient failures.
+    });
+  }, CHAT_HEARTBEAT_INTERVAL_MS);
+
+  resyncChat();
+}
+
+/**
+ * Serializes arming per connection: the reconnect handler and connectChatHub both reach
+ * for an arm on a fresh socket, and the reconnect one parks on the connection lock, so
+ * without sharing the operation the second issues a duplicate `Connect` and the two runs
+ * race each other's retry timer.
+ *
+ * `resetAttempts` accompanies a new connection id, which always deserves a full budget.
+ */
+function armChatSession(options?: { resetAttempts?: boolean }): Promise<void> {
+  if (options?.resetAttempts) {
+    chatArmAttempts = 0;
+  }
+
+  if (chatArmOperation) {
+    return chatArmOperation;
+  }
+
+  const operation = runChatArm().finally(() => {
+    if (chatArmOperation === operation) {
+      chatArmOperation = null;
+    }
+  });
+  chatArmOperation = operation;
+  return operation;
+}
+
 /** Minimal shape of the SignalR weather alert payload. The server sends
  *  WeatherAlertId as the primary identifier, matching WeatherAlertResultData. */
 interface WeatherAlertSignalRMessage {
@@ -406,7 +498,7 @@ export const useSignalRStore = create<SignalRState>((set, get) => ({
       });
 
       const chat = useChatStore.getState();
-      const handlerMap: Record<string, (raw: unknown) => void> = {
+      const handlerMap: Record<string, (...args: unknown[]) => void> = {
         chatMessageReceived: chat.handleMessageReceived,
         chatMessageEdited: chat.handleMessageEdited,
         chatMessageDeleted: chat.handleMessageDeleted,
@@ -424,7 +516,7 @@ export const useSignalRStore = create<SignalRState>((set, get) => ({
       };
 
       Object.entries(handlerMap).forEach(([event, handler]) => {
-        const wrapped = (data: unknown) => handler(data);
+        const wrapped = (...args: unknown[]) => handler(...args);
         chatHubHandlers[event] = wrapped;
         signalRService.on(event, wrapped);
       });
@@ -432,21 +524,41 @@ export const useSignalRStore = create<SignalRState>((set, get) => ({
       const onChatConnected = () => {
         logger.info({ message: 'Connected to chat SignalR hub' });
         set({ isChatHubConnected: true, error: null });
-        useChatStore.getState().handleChatConnected();
+        resyncChat();
       };
       chatHubHandlers.onChatConnected = onChatConnected;
       signalRService.on('onChatConnected', onChatConnected);
 
-      // Announce chat presence to the hub, then begin the periodic heartbeat.
-      await signalRService.invoke(Env.CHAT_HUB_NAME, 'Connect');
-      set({ isChatHubConnected: true });
+      // A dropped transport reconnects with a fresh connection id that belongs to no
+      // channel groups, so it has to announce itself again or the socket stays open and
+      // silent. The service already raises these per-hub lifecycle events.
+      const chatReconnected = `${SignalRService.HUB_RECONNECTED_EVENT}:${Env.CHAT_HUB_NAME}`;
+      const chatDisconnected = `${SignalRService.HUB_DISCONNECTED_EVENT}:${Env.CHAT_HUB_NAME}`;
 
-      stopChatHeartbeat();
-      chatHeartbeatTimer = setInterval(() => {
-        signalRService.invoke(Env.CHAT_HUB_NAME, 'Heartbeat').catch(() => {
-          // Heartbeat is best-effort; ignore transient failures.
+      const onChatReconnected = () => {
+        void armChatSession({ resetAttempts: true }).catch(() => {
+          // runChatArm already logged and scheduled its retry.
         });
-      }, CHAT_HEARTBEAT_INTERVAL_MS);
+      };
+      chatHubHandlers[chatReconnected] = onChatReconnected;
+      signalRService.on(chatReconnected, onChatReconnected);
+
+      const onChatDisconnected = () => {
+        stopChatHeartbeat();
+        stopChatArmRetry();
+        // The debounce only guards duplicates within one connection; carrying the marker
+        // across the gap would swallow the resync that backfills the outage.
+        lastChatResyncAt = 0;
+        // Clearing the flag is what lets connectChatHub repair the session later; while it
+        // stayed true the hub could never be re-announced.
+        set({ isChatHubConnected: false });
+      };
+      chatHubHandlers[chatDisconnected] = onChatDisconnected;
+      signalRService.on(chatDisconnected, onChatDisconnected);
+
+      // Announce chat presence to the hub, then begin the periodic heartbeat.
+      await armChatSession({ resetAttempts: true });
+      set({ isChatHubConnected: true });
 
       logger.info({ message: 'Chat hub handlers registered successfully' });
     } catch (error) {
@@ -458,6 +570,9 @@ export const useSignalRStore = create<SignalRState>((set, get) => ({
   disconnectChatHub: async () => {
     try {
       stopChatHeartbeat();
+      stopChatArmRetry();
+      chatArmAttempts = 0;
+      lastChatResyncAt = 0;
       unregisterChatHubHandlers();
       await signalRService.disconnectFromHub(Env.CHAT_HUB_NAME);
       set({ isChatHubConnected: false });