Open MRs are not counted correctly on dashboard and in side menu

Summary

Some of my projects show another number of open MRs in dashboard and side menu than in the MR view.

Steps to reproduce

The affected projects had several days old MRs that have been closed recently. And no new MRs have been pushed since then. I can look more closely if needed.

Example Project

https://gitlab.com/authentic-xchkskowq/authentic_scan/ (private repository)

What is the current bug behavior?

The count on the overviews seems to stay where the old value was, despite MRs having been closed.

What is the expected correct behavior?

The number of MRs on the dashboard and in the side menu should be the same as in the MR view

Relevant logs and/or screenshots

Screenshot from the project linked above:

Output of checks

This bug happens on GitLab.com

Possible fixes

Maybe this is a caching issue and will be "solved" again as soon as there are new MRs.