This appeared in the bug database today, and it sounds like it might be the culprit.
(If so, it has been marked fixed for 4.25.2!)
Update: I also just received a reply to my bug submission. (For context I said I was unable to find a reliable way to make a machine without the issue start repro’ing it)
"This is not something we have been able to reproduce either. Reports we have received have mentioned removing the File Explorer plugins have resolved the issue for them. We are looking into to see if it is an issue with Engine. That issue can be tracked here: Unreal Engine Issues and Bug Tracker (UE-93999) "
(Note that that’s a different bug listing though likewise marked fixed for 4.25.2 (in the same commit), but presumably the fix can’t be confirmed because they don’t have a repro to test it on)