Since I originally posted this, I went ahead and performed a check switch, followed by a full reboot of both 722k receivers. This has seemed to help quite a bit.
This is happening now only on recorded events from what I can tell. It is most noticed on our recordings of Falling Skies on TNT originally recorded in 2011 and 2012. These episodes are on our external hard drive and being played directly off that external drive. My wife and I are just now getting to watching these episodes.
I use the 30 second skip to fast forward commericals. It seems to lose CC after play resumes at the end of the commercial break. Now it appears that the CC seems to return within about 30 seconds to 1 minute after resuming play. Also, this doesn't necessarily happen after every commercial break, just some of them with no discernable pattern to it that I have noticed.
Since L800 was released recently, I just wondered if there was a code bug that might be affecting CC.