OK, so I'm stumped. After spending the evening going through Time Machine backups to find random episodes of podcasts that iTunes deleted in the upgrade to 11.2 I can't find an answer: That's the difference between "My Episodes" and "Saved" episodes? In the list view, I change the filter between "Unplayed/My Episodes" and "Saved" and the listing of episodes seems to change at random. I collect podcasts like some people collect comic books. Many of the shows I've got aren't around any more, and no longer have feeds active, so this random loss of files from disk is frankly disturbing.