Incosistent login responses between osx and ubuntu AND unsuccesful pushes

Hi

I am trying to push a tagged image to AWS ECR
For some reason, this does not work on ubuntu (github actions runners)
The responses from client.images.push(...) just hit exponential backoff:

{'status': 'Preparing', 'progressDetail': {}, 'id': '994393dc58e7'}
{'status': 'Waiting', 'progressDetail': {}, 'id': '994393dc58e7'}
{'status': 'Retrying in 5 seconds', 'progressDetail': {}, 'id': 'de1bc4ba6c4b'}  # <-- This repeats with larger retry values until EOF
{'errorDetail': {'message': 'EOF'}, 'error': 'EOF'}

While trying to debug this, I ran into this inconsistency, and was wondering if anyone could shine some light on it:

When running docker.DockerClient().login(...) with AWS ECR credentials plugged in, on macos, the response is:

{'IdentityToken': '', 'Status': 'Login Succeeded'}

on ubuntu it is:

{'username': 'AWS', 'password': '...', 'email': None, 'serveraddress': '***.dkr.ecr.eu-west-1.amazonaws.com'}

Thanks

No source file or test is named. Start by reproducing DockerClient.login and client.images.push with AWS ECR credentials on macOS and Ubuntu, including a GitHub Actions runner, then compare the returned login data and push output. Done means the platform-dependent login behavior and failed push are explained or corrected, with coverage for the affected behavior.