Sometimes when I'm fast forwarding or rewinding a show, the show suddenly and very quickly rewinds all the way to the beginning of the show. 

When this happens, I can see the scroll bar move to the left far more quickly than even the "Lightening" rewind. That is, 2 hours will rewind in about a second. I have to then fast forward manually to find my place in the show. This happens when I am watching a hockey game and I might rewind a bit to watch a replay, or when I FF through a commercial. It doesn't always happen - it's only once or twice during a game, but there's no unusual key entry on the remote control that I'm aware that I might be doing. 

Thanks for any suggestions!!