Job not recognized by other comitters

I have a .gitlab-ci.yml very near if not identical to the informations provided by GitLab Container Registry | GitLab

  image: docker:19.03.12
  stage: build
    - docker:19.03.12-dind
    - docker build -f .docker/backend/Dockerfile -t $IMAGE_TAG .
    - docker push $IMAGE_TAG

If I push a change everything seems fine: A pipeline is started that succeed: 1 job for develop in 2 minutes and 23 seconds

However if other developers are pushing to the same branch the pipeline fails with 0 jobs for develop.

If I now manually trigger a pipeline run from the webinterface, select develop as branch (no variables provided) then his commit also can be built perfectly fine.

Maybe I misconfigured something I don’t know of?
I tried to google for that but it seems I am missing the right direction to search for.

+1 here. New developers are triggering pipeline with no jobs. Even the “Run Pipeline” button doesn’t work them (while working for me).