Repository: langchain
Issue: SqliteCache fails with ChatOpenAI.with_structured_output(method="json_schema")
Labels: 🤖:bug,investigate

### Checked other resources

- [X] I added a very descriptive title to this issue.
- [X] I searched the LangChain documentation with the integrated search.
- [X] I used the GitHub search to find a similar question and didn't find it.
- [X] I am sure that this is a bug in LangChain rather than my code.
- [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

```python

from langchain.globals import set_llm_cache
from langchain_community.cache import SQLiteCache
from langchain_core.messages import SystemMessage
from langchain_openai import ChatOpenAI
from pydantic import BaseModel

from dotenv import load_dotenv

_ = load_dotenv()

class Limerick(BaseModel):
    limerick: str

def main():
    set_llm_cache(SQLiteCache())
    llm = ChatOpenAI(model_name="gpt-4o-2024-08-06")
    structured_llm = llm.with_structured_output(Limerick, method="json_schema")
    for _ in range(2):
        result = structured_llm.invoke([SystemMessage(content="Write a limerick")])
        print(result)

if __name__ == "__main__":
    main()
```


### Error Message and Stack Trace (if applicable)

  File "/usr/local/lib/python3.12/site-packages/langchain_core/runnables/base.py", line 3022, in invoke
    input = context.run(step.invoke, input, config, **kwargs)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/langchain_core/runnables/base.py", line 5354, in invoke
    return self.bound.invoke(
           ^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/langchain_core/language_models/chat_models.py", line 286, in invoke
    self.generate_prompt(
  File "/usr/local/lib/python3.12/site-packages/langchain_core/language_models/chat_models.py", line 786, in generate_prompt
    return self.generate(prompt_messages, stop=stop, callbacks=callbacks, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/langchain_core/language_models/chat_models.py", line 643, in generate
    raise e
  File "/usr/local/lib/python3.12/site-packages/langchain_core/language_models/chat_models.py", line 633, in generate
    self._generate_with_cache(
  File "/usr/local/lib/python3.12/site-packages/langchain_core/language_models/chat_models.py", line 818, in _generate_with_cache
    return ChatResult(generations=cache_val)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/pydantic/main.py", line 212, in __init__
    validated_self = self.__pydantic_validator__.validate_python(data, self_instance=self)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pydantic_core._pydantic_core.ValidationError: 1 validation error for ChatResult
generations.0
  Input should be a valid dictionary or instance of ChatGeneration [type=model_type, input_value=Generation(text='{"lc": 1...id_tool_calls": []}}}}'), input_type=Generation]
    For further information visit https://errors.pydantic.dev/2.9/v/model_type


### Description

Trying to use ChatOpenAI(model_name="gpt-4o-2024-08-06") with "json_schema".  issue is not seen with "json_mode" 



### System Info

System Information
------------------
> OS:  Linux
> OS Version:  #1 SMP PREEMPT_DYNAMIC Mon Aug 12 08:48:58 UTC 2024
> Python Version:  3.12.7 (main, Oct  1 2024, 22:28:49) [GCC 12.2.0]

Package Information
-------------------
> langchain_core: 0.3.10
> langchain: 0.3.3
> langchain_community: 0.3.2
> langsmith: 0.1.133
> langchain_openai: 0.2.2
> langchain_text_splitters: 0.3.0
> langgraph: 0.2.35

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> aiohttp: 3.10.9
> async-timeout: Installed. No version info available.
> dataclasses-json: 0.6.7
> httpx: 0.27.2
> jsonpatch: 1.33
> langgraph-checkpoint: 2.0.1
> numpy: 1.26.4
> openai: 1.51.2
> orjson: 3.10.7
> packaging: 24.1
> pydantic: 2.9.2
> pydantic-settings: 2.5.2
> PyYAML: 6.0.2
> requests: 2.32.3
> requests-toolbelt: 1.0.0
> SQLAlchemy: 2.0.35
> tenacity: 8.5.0
> tiktoken: 0.8.0
> typing-extensions: 4.12.2
root@77355f84363e:/usr/src/app#