diff --git a/ui/src/ui/app.test.ts b/ui/src/ui/app.test.ts
index 1373a0657c4..fda82e42432 100644
--- a/ui/src/ui/app.test.ts
+++ b/ui/src/ui/app.test.ts
@@ -136,6 +136,10 @@ describe("OpenClawApp dictation recorder lifecycle", () => {
     await app.toggleChatDictation();
     const recorder = MockMediaRecorder.instances[0];
     recorder.emitData(new Blob(["audio"], { type: "audio/webm" }));
+    transcribeChatAudioMock.mockImplementationOnce(async () => {
+      expect(app.chatDictationChunks).toEqual([]);
+      return null;
+    });
 
     await app.toggleChatDictation();
 
diff --git a/ui/src/ui/app.ts b/ui/src/ui/app.ts
index c76913f36fa..3cc6c012ab6 100644
--- a/ui/src/ui/app.ts
+++ b/ui/src/ui/app.ts
@@ -1016,7 +1016,7 @@ export class OpenClawApp extends LitElement {
         if (this.chatDictationRecorder !== recorder) {
           return;
         }
-        const chunks = this.chatDictationChunks;
+        const chunks = [...this.chatDictationChunks];
         this.chatDictationChunks = [];
         const canceledByRequest = this.chatDictationCancelNextStop;
         this.chatDictationCancelNextStop = false;