diff --git a/litellm/integrations/custom_guardrail.py b/litellm/integrations/custom_guardrail.py
index 312fd2a542c..6825d2fd2a0 100644
--- a/litellm/integrations/custom_guardrail.py
+++ b/litellm/integrations/custom_guardrail.py
@@ -922,12 +922,18 @@ class CustomGuardrail(CustomLogger):
         requested: Final = next((bucket.get("guardrails") for bucket in buckets if "guardrails" in bucket), None)
         if name not in _str_collection(requested):
             return
+        named_lists: Final = tuple(
+            cast("list[object]", bucket["applied_guardrails"])  # cast-ok: entries are only compared with names
+            for bucket in buckets
+            if isinstance(bucket.get("applied_guardrails"), list)
+        )
+        for applied in named_lists:
+            if name not in applied:
+                applied.append(name)
+        if named_lists:
+            return
         metadata_bucket: Final = cast("dict[str, object]", get_or_create_metadata_bucket(data)[1])  # cast-ok: str keys
-        applied: Final = metadata_bucket.get("applied_guardrails")
-        if not isinstance(applied, list):
-            metadata_bucket["applied_guardrails"] = [name]
-        elif name not in applied:
-            cast("list[object]", applied).append(name)  # cast-ok: entries are only compared with names
+        metadata_bucket["applied_guardrails"] = [name]
 
     @classmethod
     def uses_apply_guardrail_interface(cls) -> bool:
diff --git a/tests/unit/proxy/utils/proxy_logging/test_guardrail_pipeline.py b/tests/unit/proxy/utils/proxy_logging/test_guardrail_pipeline.py
index 39f4e9a10ef..b02b5aecb8a 100644
--- a/tests/unit/proxy/utils/proxy_logging/test_guardrail_pipeline.py
+++ b/tests/unit/proxy/utils/proxy_logging/test_guardrail_pipeline.py
@@ -1843,6 +1843,32 @@ async def test_deployment_hook_names_a_pipeline_step_it_ran_before_any_guardrail
     assert metadata["applied_guardrails"] == ["second"]
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("named_bucket", ["metadata", "litellm_metadata"])
+async def test_deployment_hook_names_a_pipeline_step_next_to_the_steps_already_named_when_both_buckets_exist(
+    named_bucket: str,
+) -> None:
+    guardrail: Final = _PipelineStepGuardrail("second", "pre_call")
+    metadata: Final[dict[str, object]] = {
+        "guardrails": ["first", "second"],
+        "_pipeline_managed_guardrails": frozenset({"first", "second"}),
+    }
+    litellm_metadata: Final[dict[str, object]] = {}
+    {"metadata": metadata, "litellm_metadata": litellm_metadata}[named_bucket]["applied_guardrails"] = ["first"]
+    kwargs: Final[dict[str, object]] = {
+        "model": "m",
+        "messages": [{"role": "user", "content": "hi"}],
+        "guardrails": ["second"],
+        "metadata": metadata,
+        "litellm_metadata": litellm_metadata,
+    }
+
+    await guardrail.async_pre_call_deployment_hook(kwargs=kwargs, call_type=CallTypes.completion)
+
+    assert guardrail.calls == 1
+    assert sorted(get_logging_caching_headers(kwargs)["x-litellm-applied-guardrails"].split(",")) == ["first", "second"]
+
+
 @pytest.mark.asyncio
 async def test_deployment_hook_records_a_pipeline_step_it_ran_without_naming_one_the_request_did_not_list() -> None:
     guardrail: Final = _PipelineStepGuardrail("second", "pre_call")