Group labels - database issue ?

Summary

I wanted to checkout the new Group Labels & I found out that, when I create it, the list of open issues & merge requests is not right and the list is loading really slow.
Also when I created a second one, it would not even load! (Fixed by removing them from a labels list under any project) - it would show 502 error.

Steps to reproduce

Create issue labels like Enhancement, Bug or similar.

Expected behavior

Very similar experience as with the project scoped labels.

Actual behavior

Sloppy loading times, inaccurate listing.

Relevant logs and/or screenshots

Possible fixes

I don't know the inner works of GitLab, so ...