I have been having issues with recorded shows for the past few months where when I am trying to watch something and the show will momentarily hang and then skip forward multiple seconds and sometimes even minutes. It is very similar to a DVD with a scratch on it that will freeze and then resume playing further down the road.
The issue happens whether I try to watch a show on my main DVR-connected TV, or the secondary TVs, or the XTV site, or the Xfinity Stream app. The only way I am able to watch shows without any issues is either live or via Xfinity On Demand (both of which I am unable to fast forward through).
I saw similar posts on these forums but never saw a clear solution. I have switched out my main DVR unit and the problem persists.
Sure sounds like some kind of communication issue with the backend server/plant/whatever. Comcast might not charge you to check the line from your residence back to the server.