diff --git a/libs/core/langchain_core/language_models/chat_models.py b/libs/core/langchain_core/language_models/chat_models.py
index f37113b4661e6..0556a708a9a5c 100644
--- a/libs/core/langchain_core/language_models/chat_models.py
+++ b/libs/core/langchain_core/language_models/chat_models.py
@@ -1128,7 +1128,15 @@ def _generate_with_cache(
         if check_cache:
             if llm_cache:
                 llm_string = self._get_llm_string(stop=stop, **kwargs)
-                prompt = dumps(messages)
+                normalized_messages = [
+                    (
+                        msg.model_copy(update={"id": None})
+                        if getattr(msg, "id", None) is not None
+                        else msg
+                    )
+                    for msg in messages
+                ]
+                prompt = dumps(normalized_messages)
                 cache_val = llm_cache.lookup(prompt, llm_string)
                 if isinstance(cache_val, list):
                     converted_generations = self._convert_cached_generations(cache_val)