diff --git a/docs/memory/claude_inventory_validation_20260513.md b/docs/memory/claude_inventory_validation_20260513.md
index b768fa9..03180e2 100644
--- a/docs/memory/claude_inventory_validation_20260513.md
+++ b/docs/memory/claude_inventory_validation_20260513.md
@@ -22,6 +22,7 @@
 - OpenClaw Bot：中文字型下載、趨勢同期 DB 查詢、匯入格式業績預覽解析等 best-effort 區塊已補 debug/exception/warnings，避免真正錯誤完全無跡可查。
 - Telegram polling bot：舊 callback 正規化失敗、空 `momo:eig:` event_id 回覆失敗仍保持 fail-safe，但已補 debug log。
 - `ai_call_logger._write_to_db` 不是死函數：它是 `_async_write()` 的 daemon thread target；decorator token 自動抽取與 stack caller 推斷的 best-effort 失敗也已補 debug log。
+- `cache_manager.FingerprintCache` 與 dashboard shared cache 清理維持 fail-open / best-effort，但已補 debug log，避免 cache fingerprint 或檔案清理失敗完全沉默。
 
 ## 已驗證為已修或過期
 
@@ -83,3 +84,4 @@
 - `89c400d` 補上 OpenClaw best-effort 區塊紀錄
 - `ec5a22d` 記錄 Telegram pending action 驗證
 - `f44c429` 補強 AI logger best-effort 診斷
+- `8a36856` 補強 Telegram callback 診斷
diff --git a/services/cache_manager.py b/services/cache_manager.py
index 385ea4a..ba280e8 100644
--- a/services/cache_manager.py
+++ b/services/cache_manager.py
@@ -8,10 +8,14 @@ module-level cache 收斂到這裡，避免各 route 各自持有一份 dict。
 """
 
 import os
+import logging
 import time
 from pathlib import Path
 
 
+logger = logging.getLogger(__name__)
+
+
 class FingerprintCache:
     """TTL + fingerprint 的小型 in-memory cache。"""
 
@@ -30,13 +34,14 @@ class FingerprintCache:
             if self._fp_fn() != entry['fp']:
                 return None
         except Exception:
-            pass
+            logger.debug("cache fingerprint check failed for %s", self.name, exc_info=True)
         return entry['data']
 
     def set(self, key, data):
         try:
             fp = self._fp_fn()
         except Exception:
+            logger.debug("cache fingerprint write failed for %s", self.name, exc_info=True)
             fp = None
         self._store[key] = {'data': data, 'ts': time.time(), 'fp': fp}
 
@@ -137,4 +142,4 @@ def clear_dashboard_cache():
     except FileNotFoundError:
         pass
     except OSError:
-        pass
+        logger.debug("dashboard shared cache cleanup failed", exc_info=True)