I'm glad I found this thread. I've been experiencing the Joey pixelization issue for about 6 months. I have a H3 w/OTA, and 2 J3's. DISH has been out twice. First, they put a new cable on one of the Joey's from the wall. Of course, that didn't help. They replaced the H3 last time. It helped for 2 days, then right back to the pixelization. For me, switching to an OTA channel and back to a satellite channel doesn't help. The H3 has to be rebooted. I am hesitant to call DISH again, because they don't seem to have a clue, and they will just send a tech back out.
My H3/OTA are behind the TV (TV is above the fireplace), and I've noticed that if the H3 connected TV has been on for a few hours, and then I go to the TV with the J3, that is when I get the pixelization. If the H3 TV has not been on, the Joey TV's will work fine. That does lead me to believe it's a heat related issue, but doesn't explain why a H3 reboot cures it.
I'm hopeful that the next software release will help.