Fast forwarding on a DVR program currently recording sometimes shows the very beginning of the show

For instance, if I'm watching a sporting event that has recorded 1 hour and 47 minutes of the game and I have watched 32 minutes of it, while I fast forward through a 3 minute commercial instead of playing the show at the 35 minute mark, it starts playing the show at the very beginning. When I pause the show it shows I'm at the 35 minute mark even though the video on the screen is footage that was shown at the very beginning of the show (:01 minute mark). This only happens on shows currently being recorded, never shows that have finished recording.