Making a new library works, along with a new shared folder.
However if i copy all the shows to a new shared folder, and delete the old one. Then delete the library from plex, and rename the shared folder to what I want.
Re-adding to plex does pick up all the old files. But it still doesn’t detect new files automatically.
Any chance it can be the number of files in the library, not the number of folders as per this page