For those who might be interested, I decided to exchange my camera for another. While it's possible I just tickled it in a way others had not (I think that's unlikely as I've only taken 2,600 photos over 6 time separate sessions), it's also possible that the issue was something like a cracked board or another similarly hard to reproduce and/or track down error.
So, for my own peace of mind, I decided to try my hand with another one.
Shawn L.