diff --git a/app/core/observe_worker.py b/app/core/observe_worker.py
index ba44a6e..aa41723 100644
--- a/app/core/observe_worker.py
+++ b/app/core/observe_worker.py
@@ -104,6 +104,9 @@ async def stop_observe_worker(task: asyncio.Task | None) -> None:
     task.cancel()
     with contextlib.suppress(asyncio.CancelledError):
         await task
+    dropped = take_dropped()  # 收口:补记最后一个 flush 窗口累计的丢弃数,不让账丢在关停期
+    if dropped:
+        logger.warning("observe dropped %d events (queue full) before shutdown", dropped)
     if _client is not None:
         # worker 已停,安全 drain 剩余并 best-effort 发最后一批(短超时,不卡关停);
         # 超过一批(BATCH_MAX)的剩余直接丢,不做多轮 flush(best-effort,关停从速)。