TV Screen Keeps Pixelating

I have 3 tv set top boxes and all three of my tv screens keep pixelating. About every 30 seconds or so the screen gets distorted and blurred. (This does not happen if I am streaming Prime or Hulu so I’m assuming it’s an Xfinity problem). I have been through all the troubleshooting with the assistant. I’ve restarted, done a system reset, made sure all cords/lines are tightened, and still the problem persists. I’m not sure if this is a neighborhood-wide issue or if it’s just my signal. Anyone else ever experience this? Can the support team here help or do I need to get a technician out to the house? This has been going on for a few weeks now. Tired of seeing distorted images. Thanks for any help!