Roadmap completely disappeared


I recently upgraded my self-hosted GitLab to version 13.8.3-ee and all of a sudden the roadmaps feature is broken. I have multiple epics and numerous milestones but instead of showing the roadmap Gitlab tells me:

The roadmap shows the progress of your epics along a timeline
To view the roadmap, add a start or due date to one of your epics in this group or its subgroups; from Dec 1, 2020 to Jul 31, 2021.

I can even create new epics without GitLab noticing them in the roadmap view.

Can anyone reproduce this bug? Please don’t tell me this is a feature ;D