Thanks, James! Yes, that helped. I hadn't been to the home page yet, and might have missed it again.
Apparently I had missed assigning an episode of the day for July 16th. Considering how long I've been running that, it must have happened at least a couple of times before, but I never noticed it and nobody ever mentioned it.
It's fixed now, and I'll double check to make sure that I haven't missed any other dates.