Amazon Bedrock PluginInvokeError 0.0.49

I’m getting the following error in some random interactions in my chatflow.

Failed to transform agent message: req_id: {{id}} PluginInvokeError: {“args”:{},“error_type”:“Exception”,“message”:"read llm model failed: request failed: req_id: {{id}} PluginInvokeError: {\“args\”:{\“description\”:\"1 validation error for LLMResultChunk\\nmodel\\n Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]\\n For further information visit [https://errors.pydantic.dev/2.12/v/string_type\"},\“error_type\”:\“InvokeError\”,\“message\”:\"1](https://errors.pydantic.dev/2.12/v/string_type%22%7D,%22error_type%22:%22InvokeError%22,%22message%22:%221) validation error for LLMResultChunk\\nmodel\\n Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]\\n For further information visit [https://errors.pydantic.dev/2.12/v/string_type\“}”}](https://errors.pydantic.dev/2.12/v/string_type%22%7D%22%7D)

Do you know why this happens and how to solve it permanently?