Wanted to throw my 2 cents in-- If your project was run on a Mac, MacOS will add .DS_Store files to your folders. These store meta data that only Mac uses and you can remove them on Windows. Sometimes they get committed or copied over. Unreal wasn’t showing these files in the Conntent browser but couldnt remove the folder because it wasn’t truly empty.
5.3.2 still an issue with MetaHuman animation folders.
Sometimes the folder doesn’t respond to DELETE even after fixing redirectors, in which case the only sensible thing I can see doing is going into File Explorer and manually deleting an empty folder.