Unable to pull images from registry.redhat.io when using short image names in RHOCP 3

Issue

• The deployment fails with below error message when short image names used.

  Failed to pull image "<image-name>": rpc error: code = Unknown desc = repository docker.io/<image-name> not found: does not exist or no pull access
  

• Why does docker always try to pull the images from docker.io and not from registry.redhat.io when short image names are used in the deployment?
• Why short image names works when the images pulled manually?

• Why authentication fails with below error when the short image names used in the deployment and tried to pull image from registry.redhat.io?

  rpc error: code = Unknown desc = Get https://registry.redhat.io/v2/<image-name>/manifests/latest: unauthorized: Please login to the Red Hat Registry using your Customer Portal credentials.