Gotcha. Hmm, that is bizarre.
Assuming you have all the contents of your Zune on your desktop computer still, I would probably do a complete hard wipe, reinstall the firmware, and resync. It'll take you all frickin day (it took mine about 14-15 hours to resync), but it should clear up those problems.
I've not had those exact problems before, but I used to have some glitches to where it wouldn't change tracks, it would just stay at 0:00; some podcasts registered as days worth of playtime remaining; some tracks would say it was playing one song but be playing another. Whatever the case, usually just doing a fresh install and sync clears them up pretty quick.