openclaw 只要切換 model 一定會出現這個問題
HTTP 503: data: {"error": {"message": "litellm.ServiceUnavailableError: litellm.MidStreamFallbackError: litellm.BadRequestError: Vertex_ai_betaException BadRequestError - b'{ "error": { "code": 400, "message": "Unable to submit request because function call memory_search in the 21. content block is missing a thought_signature. Learn more: https://docs.cloud.google.com/vertex-ai/generative-ai/docs/thought-signatures\", "status": "INVALID_ARGUMENT" } } '. Received Model Group=gemini-3-flash-preview Available Model Group Fallbacks=None", "type": null, "param": null, "code": "503"}}