diff --git a/tests/system_tests/services/opa_config/config.yaml b/tests/system_tests/services/opa_config/config.yaml
index 3ef8ff7ab..216968d0b 100644
--- a/tests/system_tests/services/opa_config/config.yaml
+++ b/tests/system_tests/services/opa_config/config.yaml
@@ -5,7 +5,7 @@ services:
 bundles:
   diamond-policies:
     service: ghcr
-    resource: ghcr.io/diamondlightsource/authz-policy:0.0.20
+    resource: ghcr.io/diamondlightsource/authz-policy:0.0.21
     polling:
       min_delay_seconds: 30
       max_delay_seconds: 120
diff --git a/tests/system_tests/services/tiled_config/dls.py b/tests/system_tests/services/tiled_config/dls.py
index 85aa1cc6a..5ab3580d4 100644
--- a/tests/system_tests/services/tiled_config/dls.py
+++ b/tests/system_tests/services/tiled_config/dls.py
@@ -55,7 +55,7 @@ def __init__(
         provider: str | None = None,
     ):
         self._token_audience = token_audience
-        self._type_adapter = TypeAdapter(DiamondAccessBlob)
+        self._type_adapter = TypeAdapter(DiamondAccessBlob | int)
 
         super().__init__(
             authorization_provider=authorization_provider,
@@ -80,7 +80,7 @@ async def init_node(
         decision = await self._get_external_decision(
             self._create_node,
             self.build_input(principal, authn_access_tags, authn_scopes, access_blob),
-            ResultHolder[int],
+            ResultHolder[str],
         )
         if decision and decision.result is not None:
             return (True, {"tags": [decision.result]})
@@ -131,11 +131,11 @@ def build_input(
             and "tags" in access_blob
             and len(access_blob["tags"]) > 0
         ):
-            if isinstance(tags := access_blob["tags"][0], str):
-                blob = self._type_adapter.validate_json(tags)
+            blob = self._type_adapter.validate_json(access_blob["tags"][0])
+            if isinstance(blob, DiamondAccessBlob):
                 _input.update(blob.model_dump())
-            elif isinstance(tags, int):
-                _input["session"] = str(tags)
+            elif isinstance(blob, int):
+                _input["session"] = str(blob)
 
         return json.dumps({"input": _input})
 
@@ -151,7 +151,7 @@ async def filters(
         tags = await self._get_external_decision(
             self._user_tags,
             self.build_input(principal, authn_access_tags, authn_scopes),
-            ResultHolder[list[int | str]],
+            ResultHolder[list[str]],
         )
         if tags is not None:
             if tags.result == ["*"]: