This has been happening to me too - see here for my recent post. My 'solution' is to make sure it's on some channel that has no sound overnight. Cbeebies doesn't wakeup until 6am, for example, and there are others. Who thought having the box come back in a 'woken up' state after being reset was a good idea?
Thank you for coming in and posting your message, welcome into the Community.
This looks like it's turning on during the updating hours of 1am and 6am, but this isn't definitive, it depends on the box. I would suggest that whilst this is something that happens, keeping the sound system turned off in the evening would be a good idea as mentioned.
I have tested the TiVo just in case and she's running well, which is a good sign