Cannot view old diff versions of merge request

Summary

In the Changes tab of a merge request, selecting an old version should show the corresponding diff.

Steps to reproduce

1. Create a MR.
2. Push a new commit to the branch.
3. Try to view the old diff version.

Example Project

https://gitlab.com/hahnjo/old-mr-diff, more precisely https://gitlab.com/hahnjo/old-mr-diff/-/merge_requests/1/diffs?diff_id=166787237 should show First version.

What is the current bug behavior?

I can only view the diff of the latest version.

What is the expected correct behavior?

I want to see the diff of the chosen version.

Related bugs

Might be related to #326441 (closed), but as far as I understand this is about any version of old MRs.