diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -1060,6 +1060,7 @@
 
 function threadFrozenDueToViewerBlock(
   threadInfo: RawThreadInfo | ThreadInfo,
+  communityThreadInfo: ?(RawThreadInfo | ThreadInfo),
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
diff --git a/native/chat/chat-input-bar.react.js b/native/chat/chat-input-bar.react.js
--- a/native/chat/chat-input-bar.react.js
+++ b/native/chat/chat-input-bar.react.js
@@ -300,6 +300,7 @@
   +chatMentionSearchIndex: ?SentencePrefixSearchIndex,
   +chatMentionCandidates: ChatMentionCandidates,
   +parentThreadInfo: ?ThreadInfo,
+  +communityThreadInfo: ?ThreadInfo,
   +editedMessagePreview: ?MessagePreviewResult,
   +editedMessageInfo: ?MessageInfo,
   +editMessage: (
@@ -701,6 +702,7 @@
     } else if (
       threadFrozenDueToViewerBlock(
         this.props.threadInfo,
+        this.props.communityThreadInfo,
         this.props.viewerID,
         this.props.userInfos,
       ) &&
@@ -1259,10 +1261,13 @@
   const { getChatMentionSearchIndex } = useChatMentionContext();
   const chatMentionSearchIndex = getChatMentionSearchIndex(props.threadInfo);
 
-  const { parentThreadID } = props.threadInfo;
+  const { parentThreadID, community } = props.threadInfo;
   const parentThreadInfo = useSelector(state =>
     parentThreadID ? threadInfoSelector(state)[parentThreadID] : null,
   );
+  const communityThreadInfo = useSelector(state =>
+    community ? threadInfoSelector(state)[community] : null,
+  );
 
   const userMentionsCandidates = useUserMentionsCandidates(
     props.threadInfo,
@@ -1349,6 +1354,7 @@
       chatMentionSearchIndex={chatMentionSearchIndex}
       chatMentionCandidates={chatMentionCandidates}
       parentThreadInfo={parentThreadInfo}
+      communityThreadInfo={communityThreadInfo}
       editedMessagePreview={editedMessagePreview}
       editedMessageInfo={editedMessageInfo}
       editMessage={editMessage}
diff --git a/web/chat/chat-input-bar.react.js b/web/chat/chat-input-bar.react.js
--- a/web/chat/chat-input-bar.react.js
+++ b/web/chat/chat-input-bar.react.js
@@ -83,6 +83,7 @@
   +typeaheadMatchedStrings: ?TypeaheadMatchedStrings,
   +suggestions: $ReadOnlyArray<MentionTypeaheadSuggestionItem>,
   +parentThreadInfo: ?ThreadInfo,
+  +communityThreadInfo: ?ThreadInfo,
 };
 
 class ChatInputBar extends React.PureComponent<Props> {
@@ -343,6 +344,7 @@
     } else if (
       threadFrozenDueToViewerBlock(
         this.props.threadInfo,
+        this.props.communityThreadInfo,
         this.props.viewerID,
         this.props.userInfos,
       ) &&
@@ -588,11 +590,15 @@
     const { getChatMentionSearchIndex } = useChatMentionContext();
     const chatMentionSearchIndex = getChatMentionSearchIndex(props.threadInfo);
 
-    const { parentThreadID } = props.threadInfo;
+    const { parentThreadID, community } = props.threadInfo;
     const parentThreadInfo = useSelector(state =>
       parentThreadID ? threadInfoSelector(state)[parentThreadID] : null,
     );
 
+    const communityThreadInfo = useSelector(state =>
+      community ? threadInfoSelector(state)[community] : null,
+    );
+
     const userMentionsCandidates = useUserMentionsCandidates(
       props.threadInfo,
       parentThreadInfo,
@@ -673,6 +679,7 @@
         typeaheadMatchedStrings={typeaheadMatchedStrings}
         suggestions={suggestions}
         parentThreadInfo={parentThreadInfo}
+        communityThreadInfo={communityThreadInfo}
       />
     );
   });