Probably some electronic component failing, but I have seen instances where insects (usually spiders) get into electronic devices, walk on the back of circuit boards, and create problems like what you're describing. It's not likely that's your problem, but it's a lot cheaper to get rid of a spider than to have a tech change a circuit board.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0