Collette did you even read the OP's post.. They said it wasn't happening on other channels and they had rebooted to no avail. Only thing they didn't mention from your list of questions was if it was a specific time of day but even I can infer from what they wrote that it is all the time...
Thank you for coming back to confirm the answers. I've taken another look at the test results, and just as Collette found, the power levels and other stats are spot on. Though I do notice that since the last time the TiVo® was rebooted, it has logged quite a few errors (T3 errors) which could be something, so I'd now like to arrange for a technician to call out and take a closer look for you.
I've sent you a private message to get things moving, please look to the top right of this page where you'll see a purple envelope icon, click on that and you'll see my message.
We have also experienced regular bouts of occasional freezing and pixelation on Alibi. Whilst only mildly irritating and infrequent it nevertheless should not happen on a relatively new machine. We have noticed that it mainly happens on recordings and possibly when more than one channel was recording at the same time. Hope this helps.