Clipping in buildings

There are some locations in the map that look like this:


This happens only on my server. Joining other servers, these locations are fine.
I have even installed the server from scratch, but still the same. I have tried the latest version (2907) from the artifacts server, but also the latest recommended (2430).
This happens with or without resources enabled.

What should I look into? Why does this happen?

It looks like fxserver comes with these “holes” in the map, by default. A friend found me this script to fix the holes. I had no idea…