docker pull works with strace, otherwise creds failure

[kbalk-maxar]

The command docker pull {account-id}.dkr.ecr.{region}.amazonaws.com/{image-id} (with the correct account-id, region and image-id supplied) fails with the error:

Error response from daemon: Head "https://{account-id}.dkr.ecr.{region}.amazonaws.com/v2/{image-id}": 
no basic auth credentials

If I insert strace in front of the docker pull command, the pull is successful.

docker-credential-ecr-login is in my path, I have a ~/.docker/config.json with credsStore set to "ecr-login". The .docker path and file is set to my user's UID and GID.

I also only get a ~/.ecr/log/ecr-login.log when I use strace to run the command.