Finally did the dreadful move from Unity 5 to first 2021, then 2022 and I’m honestly regretting it. This error persists (among dozens of many nonsensical ones all related to the bloatware this engine received since then.)
I don’t even do a thing in the project, no error comes up in the console: save and close and this infinite loop of “cleanup” comes up every time.
Unfortunately the best way to investigate these hangs is to look at the dump files. If you have a bug report with a dump file included I will be happy to take a look.