[Bug]: Bedrock Claude Sonnet 4 model fails with UnknownOperationException on /messages endpoint

[ishaan-jaff]

What happened?

How to reproduce:

Make a request to the /messages endpoint using model bedrock/converse/us.anthropic.claude-sonnet-4-20250514-v1:0
Observe the error response

Error:

{
  "Output": {
    "__type": "com.amazon.coral.service#UnknownOperationException"
  },
  "Version": "1.0"
}

Relevant log output

Are you a ML Ops Team?

No

What LiteLLM version are you on ?

1.75.5

Twitter / LinkedIn details

No response