Whenever watching, using the iOS Xfinity TV App, NBC programs that I recorded on my DVR, the programs randomly skip around and repeat large sections of the show. It will play 10 minutes then replay the last 5 minutes over and over but the progress bar keeps moving forward.
There are other channels that do this but it seems to be an issue with particular channels (some do it all the time while others never do)
you could try this: logout of the TV app (on the settings menu). delete the app. re-install the app and log in. That fixed a problem with my iPad mini.