What type of connection are you on? Is it DSL or fibre. If it's copper then my guess is that there is a device (like a heating pump) that's on a timer with a bi

What type of connection are you on? Is it DSL or fibre. If it's copper then my guess is that there is a device (like a heating pump) that's on a timer with a big switch thats creating a pulse of radio noise that's then echoing up and down the copper and pushing the session out of bounds. At that point the far router (in the dsl box on the road) will try and resync the connection.