As this has been after a factory reset and you don't mention how long it lasts for. I would look at the settings for power and standby and see if it's that as that can be set I think as little as 3 hours of as long as 12 after no input from the box. With the factory reset if you changed that setting in the past that would change back to default. Otherwise the timing seems very odd
It may be time to have a word with our technical team to see if they can run some trouble shooting, as this doesn't sound like something we'd expect to be happening.
