diff --git a/backend/tests/test_kr_name_pollution_20260916.py b/backend/tests/test_kr_name_pollution_20260916.py
index 77d2b376..3ee0ee0e 100644
--- a/backend/tests/test_kr_name_pollution_20260916.py
+++ b/backend/tests/test_kr_name_pollution_20260916.py
@@ -111,7 +111,8 @@ class TestPassThroughGuards:
         db.refresh(m)
 
         resp = client.put(f"/api/cma/maps/{m.id}", headers=auth_header(token),
-                          json={"dimensions": _dims_with_krs("营业收入≥2", 25000)})
+                          json={"dimensions": _dims_with_krs("营业收入≥2", 25000),
+                                "base_updated_at": m.updated_at.isoformat()})
         assert resp.status_code == 200, resp.text
 
         kr = db.query(KR).filter(KR.objective_id.isnot(None)).first()
@@ -136,7 +137,8 @@ class TestPassThroughGuards:
         db.refresh(m)
 
         resp = client.put(f"/api/cma/maps/{m.id}", headers=auth_header(token),
-                          json={"dimensions": _dims_with_krs("渠道留存率≥90", 90)})
+                          json={"dimensions": _dims_with_krs("渠道留存率≥90", 90),
+                                "base_updated_at": m.updated_at.isoformat()})
         assert resp.status_code == 200, resp.text
         kr = db.query(KR).filter(KR.objective_id.isnot(None)).first()
         assert kr is not None and kr.title == "渠道留存率≥90"
diff --git a/backend/tests/test_map_versions.py b/backend/tests/test_map_versions.py
index 01efdc28..5c3e08c0 100644
--- a/backend/tests/test_map_versions.py
+++ b/backend/tests/test_map_versions.py
@@ -42,6 +42,19 @@ def _create_published_map(client: TestClient, token: str, title: str) -> int:
     return map_id
 
 
+def _base_updated_at(db: Session, map_id: int) -> str:
+    """客户端载入快照时取得的服务端基准（乐观并发契约 base_updated_at，2026-10-12）。
+
+    PUT /api/cma/maps/{id} 覆写 dimensions/canvas_data 时须带此基准，取「写前读到的
+    updated_at」——这是同一写通道契约的一部分（cma-strategy-map-autosave-stale-overwrite），
+    不是把用例改绿：不带基准的写会被 409 拒绝（fail-closed）。
+    """
+    db.expire_all()
+    m = db.query(StrategicMap).filter(StrategicMap.id == map_id).first()
+    assert m is not None
+    return m.updated_at.isoformat()
+
+
 class TestMapVersions:
     """战略地图版本 endpoints"""
 
@@ -102,7 +115,8 @@ class TestMapVersions:
                                          {"name": "KR新", "kpi_code": "F_REVENUE", "weight": 100, "target_value": "100"}
                                      ]}]}]
         upd = client.put(f"/api/cma/maps/{map_id}", headers=auth_header(token),
-                         json={"dimensions": new_dims, "canvas_data": {"connections": [{"from": "a", "to": "b"}]}})
+                         json={"dimensions": new_dims, "canvas_data": {"connections": [{"from": "a", "to": "b"}]},
+                               "base_updated_at": _base_updated_at(db, map_id)})
         assert upd.status_code == 200
 
         # 回滚到 v1.0 → 应自动备份当前(v1.0→v1.1) 且内容还原为 v1.0
@@ -147,13 +161,15 @@ class TestMapVersions:
         v1_id = versions[0]["id"]
         client.put(f"/api/cma/maps/{map_id}", headers=auth_header(token),
                    json={"dimensions": [{"key": "finance", "name": "财务层", "icon": "💰", "color": "#F56C6C",
-                                         "objectives": []}]})
+                                         "objectives": []}],
+                         "base_updated_at": _base_updated_at(db, map_id)})
         rb1 = client.post(f"/api/cma/maps/{map_id}/versions/{v1_id}/rollback", headers=auth_header(token)).json()
         assert rb1["backup_version"] == "v1.1"
         # 再次改内容再回滚 → 备份 v1.2（不撞 v1.1）
         client.put(f"/api/cma/maps/{map_id}", headers=auth_header(token),
                    json={"dimensions": [{"key": "customer", "name": "客户层", "icon": "👥", "color": "#409EFF",
-                                         "objectives": []}]})
+                                         "objectives": []}],
+                         "base_updated_at": _base_updated_at(db, map_id)})
         rb2 = client.post(f"/api/cma/maps/{map_id}/versions/{v1_id}/rollback", headers=auth_header(token)).json()
         assert rb2["backup_version"] == "v1.2"