diff --git a/frontend/src/hooks/useAssistantSession.ts b/frontend/src/hooks/useAssistantSession.ts
index d4ef81a9..25bf03ec 100644
--- a/frontend/src/hooks/useAssistantSession.ts
+++ b/frontend/src/hooks/useAssistantSession.ts
@@ -169,7 +169,12 @@ export function useAssistantSession() {
   const selectChat = useCallback(async (chatId: string) => {
     currentChatRef.current = chatId
     setActiveChatId(chatId)
-    // Don't clear task lane yet — wait for server response to decide
+    // Clear task lane immediately to prevent the persist effect from
+    // tagging the old session's data with the new chatId (race condition).
+    // Server-side pending_task_lane will restore it below if it exists.
+    setActiveQuestions([])
+    setActiveActions([])
+    setShowTaskLane(false)
     try {
       const detail = await aiSessionsApi.getSession(chatId)
       if (currentChatRef.current !== chatId) return