Okay, it's not a huge deal, since it only happens every few days when I leave my computer running and I have a work around. Given that I haven't seen any other reports in Googling the phenomena or searching the forums here, I'm guessing it's just a weirdness with my specific setup.
I'll wait until it happens again, and collect the data. I'm also going to try it out on some other machines, to see if any of them have the same problem. Other than that glitch, I like the program enough to roll it out to other users in the organization. Obviously, I can't do that if it's going to break.