Gear indicator in the amaturator board

Hello, everybody, have the following problem. After about 10 - 15 km drive, so when the car is warm, the gear indicator jumps into the 3. Gang and flicker something, that's what he does when I've got the multifunction switch on E or S. If I turn this one on to M, the gear indicator will be right. Error reading has brought nothing, gearbox switches as always, no malfunction. So, not wild. When the car is cold, everything is back to normal. Certainly a mistake that does not occur so often, therefore the question to the experts. Who had this problem before???
Wishes all a beautiful Christmas and a happy New Year,
Peter G.

Greetings from the snowy mountain