Error 500 when displaying commits, creating merge requests


we have a problem with a particular repository inside our on premise gitlab installation.
When the dev branch is being displayed (with all the files) the “Last Commit” and “Last Update” never get loaded and the infinite loader is being displayed all the time. When I click on the “Commits” i immediately get a 500 error.
The strange thing is that this occurs just on this one particular repository, and also on like 60-70% of branches inside of it (our dev/master is also being affected).

These are the errors that I caught from the console when showing the repository files:

Error with Permissions-Policy header: Unrecognized feature: 'interest-cohort'.
GET https://gitserver/developer/platform/mobile-client/-/refs/feature_521/logs_tree/?format=json&offset=0 500
[gitlab] Something went wrong with the startup call for "/developer/platform/mobile-client/-/refs/feature_521/logs_tree/?format=json&offset=0" Error
    at axios_startup_calls.js:16
    at async axios_startup_calls.js:57
xhr.js:184 GET https://gitserver/developer/platform/mobile-client/-/refs/feature_521/logs_tree/?format=json&offset=0 500
createError.js:16 Uncaught (in promise) Error: Request failed with status code 500
    at t.exports (createError.js:16)
    at t.exports (settle.js:17)
    at XMLHttpRequest.p.onreadystatechange (xhr.js:69

We usually used slashes in our feature branch names, I thought that this may be the problem but it wasn’t (this would also still not explain why old branches does not work anymore).

And when creating a merge request for a particular branch the 500 error page gets displayed.

We are using gitlab community v14.0.1