622 here also.I have actually seen it on my OTA as well, but happens so infrequently & if I take a second to back up w/ the dvr, it will play back w/o incident. BTW, I have a 622.
I will have to try the 'DVR backup' next time I see it and see if I get the same results as you.
Unfortunately the frequency of this artifact is much greater than I would want. Granted, it doesn't happen all the time, but even one show a week I feel is excessive because it makes that show almost unbearable to watch.