### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

Greetings LiteLLM Team,

## [Quick Summary]

When i use Bedrock Passthrough Endpoint (Link: https://docs.litellm.ai/docs/pass_through/bedrock#1-using-configyaml-recommended-for-model-endpoints) I have configured `s3` and `Custom Callback API`

When i make a curl request sometimes i see that the

a) response header do not give cost (i.e cost is shown as Zero) b) same on the UI c) same as well in the S3 Bucket.

```bash

### Request (CURL)

API_ENDPOINT="http://localhost:14201" API_KEY="sk-xxxxxxxxxxxxxxxxx" MODEL_ID="bedrock-passthrough.global.anthropic.claude-sonnet-4-6" SYSTEM=$(jq '.system' data/prompt-with-cache-1h-ttl.json)

curl -s -X POST "$API_ENDPOINT/bedrock/model/$MODEL_ID/converse" \ -H "Authorization: Bearer $API_KEY" \ -H 'Content-Type: application/json' \ -d "{ \"messages\": [ { \"role\": \"user\", \"content\": [{\"text\": \"Give me 5 Kubernetes image security best practices.\"}] } ], \"inferenceConfig\": { \"maxTokens\": 4096, \"temperature\": 1 …