OK -- the problem has been tracked down and corrected (for those techies out here, it had to do with a regularly scheduled transaction log backup conflicting with a nightly index defrag without any error being logged).
So, we will be kicking off the PM cycle (11:00 AM ET) run at 2:00. The PM cycle 2 (3:00 PM ET) will then run at 5:00 today. That should bring us back to normal.
Again, we apologize for the delay today.