I have seen sound sync issues often on ABC HD (Houston, TX) since I got my 622. I don't know if the fault is my hardware, ABC, or something with the satellite transmission versus OTA. I have observed the problem both OTA and Sat HD, however. Some days it's good. Other days, it's been a full second out of sync.
Now that the new season is cranking up, I'll see how it is doing now. I've not been too worried about the hardware as ABC HD has always done unusual things here in Houston. For example, some Desperate Housewives episodes would play only the music track and not the dialog track for 10-30 minutes of the show.