Same for me. This has happened to me with I think the past two podcasts. They are not showing up in iTunes automatically, even if I tell it to look. I have to go to the iTunes store, find it, and download manually. No big deal really, but kind of baffled as to why the DIS podcast is the only one that gives me this issue.
It's happened in the past, and a fix has been to unsubscribe, and then re-subscribe, but again, I subscribe to a number of podcasts, and this is the only one, my favorite of course, that I need to do this with from time to time.