When a movie is normally encoded for an NTSC disc, it's done at 24fps (actually 23.976fps but we'll round up), and a flag is inserted to tell the DVD player to repeat every 5th field, producing the 30fps the TV needs. What's probably happened here is that the repeated field has been inserted as part of the video stream, probably due to the deleted scenes coming from videotape. If you put the 30fps video into VirtualDub-MPEG2, you'll probably see some frames are repeated as you step through.