diff --git a/horizon/tests/test_enforcer_api.py b/horizon/tests/test_enforcer_api.py
index 84052175..d7fd7534 100644
--- a/horizon/tests/test_enforcer_api.py
+++ b/horizon/tests/test_enforcer_api.py
@@ -97,6 +97,14 @@ def test_enforcer_endpoint_invalid_token_returns_401(endpoint):
     assert response.json()["detail"] == "Invalid PDP token"
 
 
+@pytest.mark.parametrize("endpoint", PROTECTED_ENFORCER_ENDPOINTS)
+@pytest.mark.parametrize("value", ["garbage", "Bearer", "Bearer ", "Bearer a b c"])
+def test_enforcer_endpoint_malformed_header_is_401_not_500(endpoint, value):
+    client = TestClient(sidecar._app)
+    response = client.post(endpoint, headers={"authorization": value}, json={})
+    assert response.status_code == status.HTTP_401_UNAUTHORIZED
+
+
 def test_health_endpoint_is_public(monkeypatch):
     monkeypatch.setattr(stats_manager, "_had_failure", False)
     client = TestClient(sidecar._app)
diff --git a/horizon/tests/test_legacy_update_routes.py b/horizon/tests/test_legacy_update_routes.py
index 8cbcdc68..d38657c6 100644
--- a/horizon/tests/test_legacy_update_routes.py
+++ b/horizon/tests/test_legacy_update_routes.py
@@ -39,19 +39,26 @@ def test_update_policy_rejects_unauthenticated(pdp: MockPermitPDP, monkeypatch):
     monkeypatch.setattr(pdp._opal.policy_updater, "trigger_update_policy", trigger)
     client = TestClient(pdp._app)
 
-    # A missing header is rejected before the handler runs: 422 while the
-    # `authorization` param has no default (FastAPI required-param validation),
-    # 401 once enforce_pdp_token gains `= None` (PER-15244 / #317). Accept both
-    # so this survives either merge order, while still failing on an accidental
-    # 200 (auth bypass) or 500. An invalid token is 401 in both regimes, and the
-    # updater must never run for an unauthenticated caller either way.
     missing = client.post("/update_policy", follow_redirects=False)
-    assert missing.status_code in (401, 422)
+    assert missing.status_code == 401
+    assert missing.json()["detail"] == "Missing Authorization header"
     invalid = client.post("/update_policy", headers={"authorization": "Bearer wrong"}, follow_redirects=False)
     assert invalid.status_code == 401
     trigger.assert_not_awaited()
 
 
+@pytest.mark.parametrize("value", ["garbage", "Bearer", "Bearer ", "Bearer a b c"])
+def test_update_policy_malformed_header_is_401_not_500(pdp: MockPermitPDP, monkeypatch, value: str):
+    trigger = AsyncMock()
+    monkeypatch.setattr(pdp._opal.policy_updater, "trigger_update_policy", trigger)
+    client = TestClient(pdp._app)
+
+    response = client.post("/update_policy", headers={"authorization": value}, follow_redirects=False)
+
+    assert response.status_code == 401
+    trigger.assert_not_awaited()
+
+
 def test_update_policy_data_triggers_updater(pdp: MockPermitPDP, auth: dict[str, str], monkeypatch):
     get_base = AsyncMock()
     monkeypatch.setattr(pdp._opal.data_updater, "get_base_policy_data", get_base)
@@ -78,14 +85,26 @@ def test_update_policy_data_rejects_unauthenticated(pdp: MockPermitPDP, monkeypa
     monkeypatch.setattr(pdp._opal.data_updater, "get_base_policy_data", get_base)
     client = TestClient(pdp._app)
 
-    # See test_update_policy_rejects_unauthenticated for the 401/422 dual regime.
     missing = client.post("/update_policy_data", follow_redirects=False)
-    assert missing.status_code in (401, 422)
+    assert missing.status_code == 401
+    assert missing.json()["detail"] == "Missing Authorization header"
     invalid = client.post("/update_policy_data", headers={"authorization": "Bearer wrong"}, follow_redirects=False)
     assert invalid.status_code == 401
     get_base.assert_not_awaited()
 
 
+@pytest.mark.parametrize("value", ["garbage", "Bearer", "Bearer ", "Bearer a b c"])
+def test_update_policy_data_malformed_header_is_401_not_500(pdp: MockPermitPDP, monkeypatch, value: str):
+    get_base = AsyncMock()
+    monkeypatch.setattr(pdp._opal.data_updater, "get_base_policy_data", get_base)
+    client = TestClient(pdp._app)
+
+    response = client.post("/update_policy_data", headers={"authorization": value}, follow_redirects=False)
+
+    assert response.status_code == 401
+    get_base.assert_not_awaited()
+
+
 def test_legacy_routes_do_not_redirect(pdp: MockPermitPDP, auth: dict[str, str], monkeypatch):
     # Lock in the fix: the aliases must call the updaters directly, never redirect
     # to the canonical routes. Clients drop Authorization on redirects, and
diff --git a/horizon/tests/test_opal_trigger_auth.py b/horizon/tests/test_opal_trigger_auth.py
index 9d0cad7c..d8c9608b 100644
--- a/horizon/tests/test_opal_trigger_auth.py
+++ b/horizon/tests/test_opal_trigger_auth.py
@@ -7,10 +7,13 @@
 The TestClient is used WITHOUT a context manager, so the app lifespan never runs (no OPAL
 policy/data fetch, no OPA process, no control-plane connection). ``raise_server_exceptions
 =False`` means a request the auth dependency *allows* through but which then fails on real
-offline I/O surfaces as a 500 response instead of raising - so an authenticated trigger
-call asserts only that it is not blocked (status != 401), not that the handler succeeds.
+offline I/O surfaces as a 500 response instead of raising. Valid-token tests boundary-mock
+the real (unstarted) updater instances hanging off ``_sidecar._opal`` with an ``AsyncMock``,
+so the handler runs to completion and the test asserts an actual 200, not just ``!= 401``.
 """
 
+from unittest.mock import AsyncMock
+
 import pytest
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
@@ -57,11 +60,26 @@ def test_trigger_route_without_token_is_401(client: TestClient, path: str):
     assert resp.json()["detail"] == "Missing Authorization header"
 
 
-@pytest.mark.parametrize("path", TRIGGER_ROUTES)
-def test_trigger_route_with_valid_token_is_not_blocked(client: TestClient, path: str):
-    # The dependency passes; the handler may 500 offline, but it must not be a 401.
-    resp = client.post(path, headers=_auth(VALID_TOKEN))
-    assert resp.status_code != status.HTTP_401_UNAUTHORIZED
+def test_policy_updater_trigger_route_with_valid_token_returns_200(client: TestClient, monkeypatch):
+    trigger = AsyncMock()
+    monkeypatch.setattr(_sidecar._opal.policy_updater, "trigger_update_policy", trigger)
+
+    resp = client.post("/policy-updater/trigger", headers=_auth(VALID_TOKEN))
+
+    assert resp.status_code == status.HTTP_200_OK
+    assert resp.json() == {"status": "ok"}
+    trigger.assert_awaited_once_with(force_full_update=True)
+
+
+def test_data_updater_trigger_route_with_valid_token_returns_200(client: TestClient, monkeypatch):
+    get_base = AsyncMock()
+    monkeypatch.setattr(_sidecar._opal.data_updater, "get_base_policy_data", get_base)
+
+    resp = client.post("/data-updater/trigger", headers=_auth(VALID_TOKEN))
+
+    assert resp.status_code == status.HTTP_200_OK
+    assert resp.json() == {"status": "ok"}
+    get_base.assert_awaited_once_with(data_fetch_reason="request from sdk")
 
 
 @pytest.mark.parametrize("path", TRIGGER_ROUTES)