I have reported this problem here several times. My stoppage is at 4:12AM with various update times. It happens mostly (always?) on the older refurbished 722 but that may be due to it recording more of the overnight movies. Latest (April 3) was 12 Angry Men on MGM, starting at 3:59 and stopped at 4:12. I was watching something else on the same recorder, I think, without an interruption. Recordings earlier and later were fine and reset was an early 12:21 AM.
Sure makes me leery of using it for such recordings.
-Ken