PutObject fails with SignatureDoesNotMatch following release of 1.36

## The problem
Issue boto/boto3#4400 (closed, 32 comments): ### Describe the bug

We're seeing intermittent signature errors when using `boto3==1.36.x` and `botocore==1.36.x` with S3 transfer acceleration enabled. Either disabling transfer acceleration or downgrading to boto3==1.35.99 allows the upload to succeed.

```
botocore.exceptions.ClientError: An error occurred (SignatureDoesNotMatch) when calling the PutObject operation: The request signature we calculated does not match the signature you provided. Check your key and signing method.
```

### Regression Issue

- [x] Select this option if this issue appears to be a regression.

### Expected...

## What to do
[jonathan343 (maintainer)]: The SignatureDoesNotMatch errors with transfer acceleration on boto3 below 1.36.0 were server-side: an intermediary was modifying the Transfer-Encoding header before S3, breaking the signature. That issue is resolved. A separate problem: third-party S3-compatible providers had checksum errors on the 1.36.x line; confirmed workarounds are pinning boto3 below 1.36.0 or setting request_checksum_calculation to when_required for low-level ops.