diff --git a/app.py b/app.py
index 9fd7f0b..64a826b 100644
--- a/app.py
+++ b/app.py
@@ -95,8 +95,8 @@ except Exception as e:
     sys_log.error(f"無法檢測磁碟空間: {e}")
 
 # 🚩 系統版本定義 (備份與顯示用)
-# 🚩 2026-05-01 V10.65: Prewarm dashboard cache and expose AI pick evidence gaps
-SYSTEM_VERSION = "V10.65"
+# 🚩 2026-05-01 V10.66: Avoid redundant dashboard prewarm rebuilds across workers
+SYSTEM_VERSION = "V10.66"
 
 # ==========================================
 # 🔒 SQL Injection 防護函數
diff --git a/config.py b/config.py
index 49b71ba..daf0991 100644
--- a/config.py
+++ b/config.py
@@ -254,7 +254,7 @@ YOUTUBE_API_KEY = os.getenv('YOUTUBE_API_KEY', '')
 # ==========================================
 # 系統版本與路徑
 # ==========================================
-SYSTEM_VERSION = "V10.65"
+SYSTEM_VERSION = "V10.66"
 LOG_FILE_PATH = os.path.join(BASE_DIR, 'logs/system.log')
 public_url = PUBLIC_URL  # 用於模板顯示
 
diff --git a/routes/dashboard_routes.py b/routes/dashboard_routes.py
index bca49e9..9521baf 100644
--- a/routes/dashboard_routes.py
+++ b/routes/dashboard_routes.py
@@ -605,10 +605,10 @@ def _write_shared_full_dashboard_cache(full_data):
             pass
 
 
-def warm_full_dashboard_cache(reason='manual'):
+def warm_full_dashboard_cache(reason='manual', force_rebuild=False):
     """供 API、排程與 Gunicorn worker 啟動時預熱商品看板完整快取。"""
     started = time.time()
-    data = get_full_dashboard_data(force_rebuild=True)
+    data = get_full_dashboard_data(force_rebuild=force_rebuild)
     duration_ms = (time.time() - started) * 1000
     sys_log.info(
         f"[Dashboard] [Cache] ✅ 預熱完成 | reason={reason} | "
diff --git a/tests/test_frontend_v2_assets.py b/tests/test_frontend_v2_assets.py
index 5a4cfe2..ae3a5cb 100644
--- a/tests/test_frontend_v2_assets.py
+++ b/tests/test_frontend_v2_assets.py
@@ -51,6 +51,7 @@ def test_dashboard_v2_is_production_default_and_uses_real_dashboard_data():
     assert "_load_stale_full_dashboard_cache(now)" in route_source
     assert "_write_shared_full_dashboard_cache(full_data)" in route_source
     assert "warm_full_dashboard_cache" in route_source
+    assert "force_rebuild=False" in route_source
     assert "_load_competitor_decision_overview(session)" in route_source
     assert "ai_price_recommendations" in route_source
     assert "pending_match_count" in route_source