There has been weird stuff going on with permissions in general on this site for a couple of years now. It’s like something is corrupt somewhere, but I’ve never been able to find out where. I may have to make a fresh installation of 3.0, set up new permissions there, import the resources from this 2.8.8 site, and update scripts as needed to see if that fixes the issues.
I have a site like that, only it’s Package Manager that’s acting weird. Packages that install fine elsewhere crash when installing on that site. I’ve been meaning to make a fresh install for a long time.