Turns out that our problem was caused by bad links being auto-generated for Wellesley tracks by the iTunes Store.
For example, when you go to the iTunes Store from a Mac or Windows PC and search for Nathan Englander Wellesley, and click the arrow next to Free on the far right to Copy Link, you get
If we modify the URL to substitute /itunes-u/ for /podcast/ and also delete the "&mt=2" from the end of the URL, so that it looks like
it now works properly on an iPad (i.e., it no longer goes to the Podcast app but instead, correctly goes to the iTunes U app and finds the track.
I'm hopeful Apple fixes their URL generator in the iTunes Store quickly......k