I've been having an odd problem with iTunes U Public starting around the 2nd of this month.
After our podcast gets uploaded to the public site, I can see it in the collection they belong to when I log into site manager but I can't see it in iTunes if I hit “View Live Page:iTunes” or "View Preview:iTunes" in collection configuration.
If I open the podcast (Edit Item) in "Feed Editor" and just re-save it, then, I can see it in iTunes if I hit the "View Preview:iTunes" in collection configuration.
Though at first I may not be able to see it in iTunes live, eventually it will show up.
Perhaps I am one of the few experiencing this problem because I am using still Podcast Producer to automatically upload to Itunes U Public.