diff --git a/litellm/proxy/litellm_pre_call_utils.py b/litellm/proxy/litellm_pre_call_utils.py
index 8397a904190..fab3dab5978 100644
--- a/litellm/proxy/litellm_pre_call_utils.py
+++ b/litellm/proxy/litellm_pre_call_utils.py
@@ -151,12 +151,13 @@ def _session_id_from_baggage(baggage: str) -> str | None:
 
 
 def _caller_set_trace_field(data: Mapping[str, object], metadata_variable_name: str, field: str) -> bool:
+    active: Final = data.get(metadata_variable_name)
+    active_mapping: Final = cast(Mapping[str, object], active) if isinstance(active, Mapping) else None
+    if active_mapping is not None and field in active_mapping:
+        return bool(active_mapping.get(field))
     promoted: Final = metadata_variable_name == "litellm_metadata" and field in LITELLM_TRACE_CONTROL_METADATA_FIELDS
-    sources: Final = (metadata_variable_name, "metadata") if promoted else (metadata_variable_name,)
-    return any(
-        isinstance(container := data.get(name), Mapping) and bool(cast(Mapping[str, object], container).get(field))
-        for name in sources
-    )
+    requester: Final = data.get("metadata")
+    return promoted and isinstance(requester, Mapping) and bool(cast(Mapping[str, object], requester).get(field))
 
 
 def _stampable_key_hash(user_api_key_dict: UserAPIKeyAuth) -> str | None:
diff --git a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
index f99eb5c9b30..4bbb6238ddf 100644
--- a/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
+++ b/tests/test_litellm/proxy/test_litellm_pre_call_utils.py
@@ -8245,6 +8245,40 @@ async def test_promoted_caller_trace_ids_beat_traceparent_and_baggage(path: str,
     assert updated["litellm_metadata"]["session_id"] == "caller-session"
 
 
+@pytest.mark.asyncio
+async def test_missing_session_id_reject_ignores_requester_session_id_shadowed_by_empty_litellm_metadata():
+    with pytest.raises(ProxyException) as exc_info:
+        await add_litellm_data_to_request(
+            data={
+                "model": "gpt-4o",
+                "input": "hi",
+                "metadata": {"session_id": "caller-session"},
+                "litellm_metadata": {"session_id": ""},
+            },
+            request=_request_for("/v1/responses"),
+            user_api_key_dict=UserAPIKeyAuth(api_key="hashed-key"),
+            proxy_config=MagicMock(),
+            general_settings={"missing_session_id": "reject"},
+        )
+    assert exc_info.value.code == "400"
+
+
+def test_add_litellm_metadata_from_request_headers_empty_litellm_metadata_field_falls_back_to_headers():
+    headers = {
+        "traceparent": "00-4bf92f3577b34da6a3ce929d0e0e4736-00f067aa0ba902b7-01",
+        "baggage": "session.id=baggage-session-42",
+    }
+    data = {
+        "metadata": {"trace_id": "caller-trace", "session_id": "caller-session"},
+        "litellm_metadata": {"trace_id": "", "session_id": ""},
+    }
+    LiteLLMProxyRequestSetup.add_litellm_metadata_from_request_headers(
+        headers=headers, data=data, _metadata_variable_name="litellm_metadata"
+    )
+    assert data["litellm_trace_id"] == "4bf92f3577b34da6a3ce929d0e0e4736"
+    assert data["litellm_session_id"] == "baggage-session-42"
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize(
     "client_body",