Norman, I've seen this a couple times with my students. Turns out they were running an older version of the app and also due to my schools slow network connection they weren't waiting long enough for the course to "refresh". I'd be interested in exchanign notes on this so we can learn what's going on.
1. What version of iTunes U is the student using?
2. Was this working before the update to iOS 6?
3. If the student closes the course and reopens it does it refresh wit the new update? In my experience this can take as little as seconds but if there is lots of courses or a slow connection it may take 10+ minutes.
4. If the student taps the home button, closes, and reopens the course does it refresh with the new update?
5. Is the student logged into the iTunes store?
Cheers and good luck.