diff --git a/frontend/src/pages/AssistantChatPage.tsx b/frontend/src/pages/AssistantChatPage.tsx
index 1f675727..b3d40d3a 100644
--- a/frontend/src/pages/AssistantChatPage.tsx
+++ b/frontend/src/pages/AssistantChatPage.tsx
@@ -259,6 +259,10 @@ export default function AssistantChatPage() {
   }, [])
 
   const handleNewChat = async () => {
+    // Invalidate currentChatRef BEFORE the await so any in-flight handleSend/handleTaskSubmit
+    // for the previous session sees a mismatch and bails — prevents stale task lane appearing
+    // in the new empty session (same pattern as selectChat, which sets ref before its await).
+    currentChatRef.current = null
     // Clear stale state immediately — don't wait for API to return
     setShowTaskLane(false)
     setActiveQuestions([])
@@ -436,6 +440,8 @@ export default function AssistantChatPage() {
   }
 
   const handleResumeNew = async (summary: string) => {
+    // Invalidate currentChatRef BEFORE the await — same guard as handleNewChat
+    currentChatRef.current = null
     // Clear stale state immediately — don't wait for API to return
     setShowTaskLane(false)
     setActiveQuestions([])