Mjpendergrass

My 2000 a8 transmission is acting funny. It seems to work great but sometimes it flips to tip tronic all on its own then I have to push the gear shift over and drive it in tip tronic. The gears are always smooth. If I push the gear over and back it goes back to normal sometimes but most of the time it just makes me drive in tip tronic. Has anyone else had this problem? Thanks so much.