I have no idea of what's going on here.
All the other albums of the same artist are alright. But Led Zeppelin I and II split into single track albums for no reason in Album & Tracks view.
In Album Covers view, the tracks are correctly grouped into the 2 albums.
I've tried to fix this by removing the tags on MP3tag, saving, then manually inputting the Artist, Album Artist, Album, Year and Track Number; nothing changed.
I've even tried to force rescan the library after; that didn't do anything either.