Wow, how frustrating! And it's weird. I definitely have the nightly reboot at that time happen, which drives me absolutely crazy since I am very much up and using the TV at that time, but I have never had it refuse to come back on.
Have you ever tried, before this happens, to manually restart your box? Sometimes, if it's right around that time, and I know I'm going to be out of the room for a couple of minutes, if it hasn't done the reboot yet, I will manually restart it. That seems to pre-empt the scheduled reboot. I would try that as soon as you get home and turn your TV on. Restart the box manually, then go get your food or drink or whatever for a couple of minutes, return and start watching and see if it still happens. Not a perfect solution, but I would be curious if it helps. I would also try manually restarting the main DVR box as well. It might be a syncing issue.