diff --git a/yunke-server/app/analytics/metrics.py b/yunke-server/app/analytics/metrics.py
index 2f5ff46..96d7c20 100644
--- a/yunke-server/app/analytics/metrics.py
+++ b/yunke-server/app/analytics/metrics.py
@@ -186,10 +186,12 @@ async def anomaly(session: AsyncSession, channel: str) -> dict | None:
         ).all()
         rows = [(d, amap.get(o, o), v) for d, o, v in raw]
 
-    # 逐 user 显式算(yesterday 量 + prev7 均值),不猜 rows 顺序
+    # 逐 user 显式算(yesterday 量 + prev7 均值),不猜 rows 顺序。
+    # 累加而非覆盖:回退路径同人(多账号映射到同一 user_id)会有多行/日。
     day_rows: dict[str, dict[int, int]] = {}
     for day, uid, v in rows:
-        day_rows.setdefault(uid, {})[day] = int(v)
+        by_day = day_rows.setdefault(uid, {})
+        by_day[day] = by_day.get(day, 0) + int(v)
 
     staff_out = []
     totals_y, totals_p = 0, 0.0
diff --git a/yunke-server/tests/test_analytics_overview.py b/yunke-server/tests/test_analytics_overview.py
index 41b3608..53605fd 100644
--- a/yunke-server/tests/test_analytics_overview.py
+++ b/yunke-server/tests/test_analytics_overview.py
@@ -55,7 +55,8 @@ async def test_overview_today(make_client, monkeypatch):
         assert out["cards"]["active_staff"] == 1
         assert out["cards"]["call_cnt"] == 1
         assert out["cards"]["first_contact"] == 1  # t1 全史 MIN(day)=今日;t2 不是
-        assert out["cards"].get("mom_total_delta") is None  # 今日无环比
+        assert "msg_total_delta" not in out["cards"]  # 今日无环比
+        assert "prev_msg_total" not in out["cards"]
 
     await make_client(seed)
 
@@ -89,3 +90,31 @@ async def test_overview_fallback_when_rollup_empty(make_client, monkeypatch):
         assert out["cards"]["msg_total"] == 3
 
     await make_client(seed)
+
+
+async def test_anomaly_fallback_multi_account(make_client, monkeypatch):
+    """回退路径同人多账号累加:wx1/wx2 同映射 u1,昨日量必须相加而非覆盖。"""
+    monkeypatch.setattr(metrics, "today_key", lambda: _TODAY)
+    async def seed(session):
+        session.add(WechatAccount(wx_id="wx1", user_id="u1"))
+        session.add(WechatAccount(wx_id="wx2", user_id="u1"))
+        # 不 seed StatDailyStaff → 走 msg_daily_stats 回退路径。
+        # 昨日(20260903)各 100(合计 200);prev7 每天各 50(日均 100)→ 偏离 +100% 触发
+        for day in [20260827, 20260828, 20260829, 20260830,
+                    20260831, 20260901, 20260902, 20260903]:
+            sent = 100 if day == 20260903 else 50
+            for wx in ("wx1", "wx2"):
+                session.add(MsgDailyStats(channel="wechat", owner_account_id=wx,
+                                          peer_kind="friend", peer_id="t1", day=day,
+                                          send_cnt=sent, recv_cnt=0,
+                                          last_ts=1788500000000,
+                                          last_is_send=True))
+        await session.commit()
+        a = await metrics.anomaly(session, channel="wechat")
+        assert a is not None
+        staff = {s["user_id"]: s for s in a["staff"]}
+        # 修复前:后写账号覆盖前写,u1 昨日只剩 100;修复后两账号累加 = 200
+        assert staff["u1"]["yesterday"] == 200
+        assert staff["u1"]["prev7_mean"] == 100.0
+
+    await make_client(seed)