Thanks but I was hoping to get a message passed on to someone in technical operations as it wasn't an issue on my end (verified the issue at multiple locations and in more than one VHO). The issue has also affected 899, HBO HD, in addition to 920 for months (none of the other HBO or Cinemax channels were affected, only the main east feeds).
I guess most viewers either didn't notice the intermittent issues or just ignored them as the errors were generally small quick flashes onscreen.
Anyway, it appears that the issue was finally resolved January 13, 2014 and both channels are error free.
Hopefully this is a permanent fix and the channels won't revert back in the near future!