"Verbose issues" with private registry images?

Hello,

I’ve experienced very strange issue with images from private registry.
Let’s imagine following situation:

docker pull mariadb:10.2
docker image tag mariadb:10.2 docker.yoda/mariadb:10.2
docker image push docker.yoda/mariadb:10.2

Now, in .gitlab-ci.yml I declare something like this:

services:
- name: mariadb:10.2
  alias: mariadb

Everything is working as expected. However… if I change gitlab-ci.yml to use docker.yoda/mariadb:10.2 instead of mariadb:10.2 - I’m receiving full verbose output of container with following warning and information about exit code 1.

*** WARNING: Service runner-42700a6e-project-56-concurrent-0-docker.yoda__mariadb-1 probably didn't start properly.

The container is up and running - the only issue are those messages in job log.
FYI: “docker.yoda” is a proxy to 127.0.0.1:5000 (Docker Registry runs on the same machine as GitLab Runner).

Do you have any clue what’s going on?