diff --git a/docs/superpowers/plans/2026-09-15-m1-data-collection-foundation.md b/docs/superpowers/plans/2026-09-15-m1-data-collection-foundation.md
index 88d7de2..5d67a8a 100644
--- a/docs/superpowers/plans/2026-09-15-m1-data-collection-foundation.md
+++ b/docs/superpowers/plans/2026-09-15-m1-data-collection-foundation.md
@@ -498,9 +498,14 @@ def test_shape_type_and_whitelist():
 def test_too_many_props_and_long_string():
     r = validate_event(_ev(properties={f"k{i}": "v" for i in range(40)}))
     assert "properties" in r
-    r = validate_event(_ev(properties={"a": "x" * 600}))
+    r = validate_event(_ev(properties={"referrer": "x" * 600}))   # 白名单内的键才能测到长度分支
     assert "properties" in r
 
+def test_nested_sensitive_key_and_naive_datetime():
+    r = validate_event(_ev(properties={"utm": {"utm_a": 1, "user_password": "x"}}))
+    assert r == "sensitive_field"                    # 嵌套层级的键也要扫
+    assert validate_event(_ev(occurred_at=NOW.replace(tzinfo=None))) == "invalid_occurred_at"
+
 def test_future_and_stale_time():
     r = validate_event(_ev(occurred_at=NOW + timedelta(days=2)))
     assert "occurred_at" in r                        # 超窗拒绝
@@ -519,7 +524,7 @@ def test_sanitize_url_drops_sensitive_params():
 ```python
 import json
 import re
-from datetime import datetime, timedelta
+from datetime import datetime
 from urllib.parse import parse_qsl, urlencode, urlparse
 from django.utils import timezone
 from tracker import constants as C
@@ -534,14 +539,29 @@ def sanitize_url(url: str) -> str:
             if not _URL_DROP_KEY.fullmatch(k)]
     return p._replace(query=urlencode(kept)).geturl()
 
-def _depth_ok(v, depth=0) -> bool:
+def _walk_props(v, depth=0):
+    """一次递归同时做深度合规与敏感键扫描（任意层级）。返回 (depth_ok, sensitive_hit)。"""
     if depth > C.MAX_PROP_DEPTH:
-        return False
+        return False, False
     if isinstance(v, dict):
-        return all(_depth_ok(x, depth + 1) for x in v.values())
+        for k, x in v.items():
+            if _SENSITIVE.search(str(k)):
+                return True, True
+            ok, hit = _walk_props(x, depth + 1)
+            if hit:
+                return True, True
+            if not ok:
+                return False, False
+        return True, False
     if isinstance(v, list):
-        return all(_depth_ok(x, depth + 1) for x in v)
-    return True
+        for x in v:
+            ok, hit = _walk_props(x, depth + 1)
+            if hit:
+                return True, True
+            if not ok:
+                return False, False
+        return True, False
+    return True, False
 
 def validate_event(ev) -> str | None:
     """返回 None 表示通过；否则返回拒绝原因码。类型/白名单/体积/深度全在此守门。"""
@@ -556,7 +576,7 @@ def validate_event(ev) -> str | None:
         if ev.get(k) is not None and not isinstance(ev[k], str):
             return "invalid_field_type"
     occ = ev.get("occurred_at")
-    if not isinstance(occ, datetime):
+    if not isinstance(occ, datetime) or timezone.is_naive(occ):
         return "invalid_occurred_at"
     skew = (timezone.now() - occ).total_seconds()
     if abs(skew) > C.CLOCK_SKEW_REJECT_SEC:
@@ -564,15 +584,16 @@ def validate_event(ev) -> str | None:
     props = ev.get("properties") or {}
     if not isinstance(props, dict) or len(props) > C.MAX_PROP_KEYS:
         return "properties_invalid"
+    depth_ok, sensitive_hit = _walk_props(props)      # 敏感键(任意层级)与深度先于白名单检查，
+    if sensitive_hit:                                  # 否则白名单会把敏感码短路成 not_allowed
+        return "sensitive_field"
     if not set(props) <= C.EVENT_PROP_WHITELIST.get(ev["event_name"], set()):
         return "property_not_allowed"
-    if not _depth_ok(props):
+    if not depth_ok:
         return "properties_depth"
     if len(json.dumps(props, ensure_ascii=False, default=str)) > C.MAX_PROP_JSON_BYTES:
         return "properties_too_large"
-    for k, v in props.items():
-        if _SENSITIVE.search(str(k)):
-            return "sensitive_field"
+    for v in props.values():
         if isinstance(v, str) and len(v) > C.MAX_STR_LEN:
             return "properties_too_long"
     if len(ev.get("path") or "") > C.MAX_PATH_LEN: