<!-- Love localstack? Please consider supporting our collective:
👉  https://opencollective.com/localstack/donate -->

# Type of request: This is a ...

[x] bug report
[ ] feature request

# Detailed description

Using node.js AWS SDK function `getObject` returns object with `0` bytes using 4566 port. 
On port 4572 it works fine.

# Steps to reproduce

## Command used to start LocalStack

```
  localstack:
    image: localstack/localstack
    networks:
      - localstack-network
    ports:
      - 4566:4566
      - 4572:4572
      - 8080:8080
    environment:
      - DEBUG=1
      - HOSTNAME_EXTERNAL=localstack
      - SERVICES=sqs,lambda,cloudwatch,s3,iam,ec2,stepfunctions,cloudwatchlogs
      - LAMBDA_REMOTE_DOCKER=false
      - LAMBDA_EXECUTOR=docker
      - LAMBDA_DOCKER_NETWORK=localstack-network
      - AWS_ACCESS_KEY_ID=123
      - AWS_SECRET_ACCESS_KEY=xyz
      - DEFAULT_REGION=us-east-1
      - DOCKER_HOST=unix:///var/run/docker.sock
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /tmp/localstack:/tmp/localstack
```

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)

```
export const s3 = new AWS.S3({
  endpoint: `http://localhost:4566`,
  s3ForcePathStyle: true,
  sslEnabled: false
});

const { Body } = await s3.getObject({
 Bucket: 'bucket',
 Key: 'file.json'
}).promise();
```
break
        if isinstance(listener_result, LambdaResponse):
            response = listener_result
            break
        if isinstance(listener_result, dict):
            response = Response()
            response._content = json.dumps(json_safe(listener_result))
            response.headers['Content-Type'] = APPLICATION_JSON
            response.status_code = 200
            break
        elif isinstance(listener_result, Request):
            modified_request = listener_result
            data = modified_request.data
            headers = modified_request.headers
            break
        elif listener_result is not True:
            
            code = listener_result if isinstance(listener_result, int) else 503
            response = Response()
            response.status_code = code
            response._content = ''
            response.headers['Content-Length'] = '0'
            append_cors_headers(response)
            return response
    
    if response is None:
        headers['Connection'] = headers.get('Connection') or 'close'
        data_to_send = data_bytes
        request_url = proxy_url
        if modified_request: