fix

src/android/onservice/NotificationService.java

@@ -359,6 +359,8 @@ public class NotificationService extends Service {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
 //            stopForeground(STOP_FOREGROUND_REMOVE);
         }
+        timer.cancel();
+        timer.purge();
         stopSelf();
         return super.onUnbind(intent);
     }