Okay, there's one more issue, unfortunately. Whenever I reexport a spine skeleton, Godot registers the change, tries to reimport the changed data, at 50% asks for my permission to access external volumes (again..) and then crashes.
This happens consistently and always. I'm not sure if it has to do with the permissions issue, but it sure crashes right after asking for those.
I'm using the C#-enabled 4.2.1 version of Godot, by the way.