diff --git a/litellm/litellm_core_utils/litellm_logging.py b/litellm/litellm_core_utils/litellm_logging.py
index c0eb3c0d729..a05cce5728e 100644
--- a/litellm/litellm_core_utils/litellm_logging.py
+++ b/litellm/litellm_core_utils/litellm_logging.py
@@ -589,7 +589,7 @@ class Logging(LiteLLMLoggingBaseClass):
         if "litellm_metadata" in kwargs and isinstance(
             kwargs["litellm_metadata"], dict
         ):
-            base_litellm_params["litellm_metadata"] = kwargs["litellm_metadata"]
+            base_litellm_params["litellm_metadata"] = kwargs["litellm_metadata"].copy()
 
         if litellm_params:
             base_litellm_params.update(litellm_params)
diff --git a/tests/test_litellm/litellm_core_utils/test_litellm_logging.py b/tests/test_litellm/litellm_core_utils/test_litellm_logging.py
index 73e9bf011d5..d1c35e15407 100644
--- a/tests/test_litellm/litellm_core_utils/test_litellm_logging.py
+++ b/tests/test_litellm/litellm_core_utils/test_litellm_logging.py
@@ -270,6 +270,8 @@ class TestUpdateFromKwargs:
         result_meta = logging_obj.litellm_params["metadata"]
         assert result_meta["from_caller"] is True
         assert result_meta["user_api_key_hash"] == "hashed-xyz"
+        # caller's dict must not be mutated by the merge
+        assert "user_api_key_hash" not in caller_metadata
 
     def test_merge_handles_metadata_none(self, logging_obj):
         """When metadata=None is explicitly in kwargs alongside litellm_metadata,