LiteLLM + Bedrock issue

I'm trying to setup MUX to work with our LiteLLM server. LiteLLM is exposes the claude sonnet 4.6 bedrock endpoint.

I have set it up the provider:
```
{
"openai": {
"apiKey": "sk-U...w",
"baseUrl": "https://litellm.our.domain/v1",
"models": [
"claude-sonnet"
]
}
}
```

I've tried the following model configs for LiteLLM

```
- model_name: claude-sonnet
litellm_params:
model: bedrock/anthropic.claude-sonnet-4-6
model_id: arn:aws:bedrock:us-east-1:6....8:application-inference-profile/75irbw5rdcvw
aws_region_name: os.environ/AWS_REGION_NAME
aws_role_name: os.environ/AWS_ROLE_ARN
aws_session_name: litellm-bedrock
```
and
```
- model_name: claude-sonnet-4-6-mux
litellm_params:
model: bedrock/anthropic.claude-sonnet-4-6
model_id: arn:aws:bedrock:us-east-1:^...8:application-inference-profile/75irbw5rdcvw
aws_region_name: os.environ/AWS_REGION_NAME
aws_role_name: os.environ/AWS_ROLE_ARN
aws_session_name: litellm-bedrock
drop_params: true
include_reasoning: false
```

I've tried enabling and disaling:
```
drop_params: true
include_reasoning: false
```

Sometimes I get errors like:
```
text part chatcmpl-b7e252dd-c0ff-4c84-8f63-a7d63e477719 not found
```

Sometimes it works - but mid way through a response I get errors like:
```
Stream Error
api

litellm.BadRequestError: BedrockException - {"message":"The number of toolResult blocks at messages.4.content exceeds the number of toolUse blocks of previous turn."}. Received Model Group=claude-sonnet
Available Model Group Fallbacks=['bedrock-claude-sonnet-4-5']
Error doing the fallback: litellm.BadRequestError: BedrockException - {"message":"The number of toolResult blocks at messages.4.content exceeds the number of toolUse blocks of previous turn."}No fallback model group found for original model_group=bedrock-claude-sonnet-4-5. Fallbacks=[{'claude-opus': ['bedrock-claude-opus-4-5']}, {'claude-sonnet': ['bedrock-claude-sonnet-4-5']}, {'claude-haiku': ['bedrock-claude-haiku-4-5']}]. Received Model Group=bedrock-claude-sonnet-4-5
Available Model Group Fallbacks=None
Error doing the fallback: litellm.BadRequestError: BedrockException - {"message":"The number of toolResult blocks at messages.4.content exceeds the number of toolUse blocks of previous turn."}No fallback model group found for original model_group=bedrock-claude-sonnet-4-5. Fallbacks=[{'claude-opus': ['bedrock-claude-opus-4-5']}, {'claude-sonnet': ['bedrock-claude-sonnet-4-5']}, {'claude-haiku': ['bedrock-claude-haiku-4-5']}]
```

Is there anything I need to do to get this working correctly?

Here's a screenshot: