I just experienced this the last 3 or 4 days. While exploring some settings I came upon an option to allow xbox to pause live tv. Heck yeah! After checking the box it immediately caused video issues. Very jerky. CNBC scrolling ticker clicked by, not scrolled. Video sharpness horrible. Jittery image. Searched for a setting to disable live tv pause but could not find one. Tried removing cable box from xbox one and starting over. That seemed to do the trick.!! Last night video back to great, and this evening all seems well.
Maybe try removing Cable box from device settings, then add it again. Then restart and ......
Let us know if it works or just coincidence.