I stumbled upon the fix for not being able to re-watch an episode. People in the forum have complained when they try to re-watch an episode it sends you back to a commercial.
So here is the fix:
If this is happening all you need to do is clear the history of the episode you are trying to view. While logged into your account, go to this link and manager history: http://xfinitytv.comcast.net/mytv/history#sort=recent