That was happening to us about 2 years ago. It was soooo inconvenient and tiresome. We had a tech come out and check things over. Everything looked good until our box tried to reboot while it wasn't connected to the tv. He gave us a new box and we haven't had any problems since then.
Hello, UnhappyPNW! Welcome to the Xfinity Forums.
I'm sorry to hear you've had to troubleshoot so much lately, I know its never a convenient task when you just want to sit down and enjoy your favorite shows. We are always adding and improving on our self-help options for troubleshooting like those in the My Account app so we are always looking for feedback on how we can ease your experience with those tools.
I would love the opportunity to see if we can make some repairs to stabilize your connection so you aren't always troubleshooting as well as making any necessary service adjustments. Please send me a private message with your first and last name, as well as your service address so I can assist.
To send a private message, click my name "ComcastTambrey", then click "send a message".