SSH port setting via ENV no longer works

we are running the GitLab CE Docker container deployed via an Ansible playbook. We provide the configuration with the environment variable GITLAB_OMNIBUS_CONFIG. This worked fine until I upgraded to 12.1.3 (11.5.3 -> 11.11.7 -> 12.1.3). Now GitLab insists on using port 22 for SSH inside the container, disregarding our configuration. Other configuration options seem to be unaffected.

The setting in question is gitlab_rails['gitlab_shell_ssh_port'] = 2222. Has there been any change to this setting recently? I didn’t see it mentioned in the release notes for the versions we skipped.