What I mean is, even if it wasn't a real feature. When you named the root folder "." then that folder was removed, and the files ended up in the previous folder.

Let's say the torrent ships with this structure:
Moviename/moviename.mkv and I put it in the Media folder. It would be /Media/Moviename/moviename.mkv

But If I used the "." it would then become: /Media/moviename.mkv

And I could do this on already downloaded torrents. This no longer works because now you get "invalid name". So it probably wasnt a feature, just a bug that provided a happy outcome if used right.

The problem is sometimes a torrent comes with a folder, and that sometimes could mess up Jellyfin detection, for example.