Push rules ignored on squash merge request

I am unsure if this is a bug and wanted to check before posting it to the issues.

We have a regex configured in our Push Rules for the repository

^([a-zA-Z]±[0-9]+: [0-9A-Z]?.*|Merge|Apply|[hH]otfix)

It is to follow the standard, that we start with our Ticket Nr (which is UNI-1234 i.e) and then a colon and the message.

This works fine for pushes, but it seems that for some time it is not applied to merge requests anymore. I remember not being able to merge because the commit message of the merge is wrong, but now it allows messages like this, which is the autogenerated merge request title

Resolve UNI-1234 “Feature XYZ”

We are squashing our commits and thus the commit message is always the merge request title in that case, but it should follow the push rules anyways…

Is this a bug or did we mess up the settings somewhere?