macOS shared runner not available for open source projects

According to documentation at

Shared macOS runners should be available for open source projects.

      - saas-macos-medium-m1
    - echo "macosx"

They doesn’t seem to work when I try. Job is getting stuck at no available runner for tag used saas-macos-medium-m1.

My project is open source at MPL-2 license. Code available at at Rdatatable / data.table · GitLab

I did register for an open source program on GitLab in the past. I have 50’000 compute minutes. So I believe I am in. Yet shared macOS runners doesn’t seem to work.

Could anyone explain if macOS runners should work for me?

If macOS shared runners are not available for open source projects, are there any plans to make them available?