Add me to the long list of people this is happening to. I just had a service tech come out and fix my cable TV issue where he got me a new amp and redirected several incoming lines to the amp. All is well there.
I recently got a new modem too from Comcast - the latest and the greatest. But this issue was happening even with the old modem/router.
I have checked all my xfi settings on the app and they only shut off specific devices of my kids when it is time to go to bed. Not sure what to do next.