I had this problem when I washed the car in cold weather and after driving for a while, the water droplets froze covering multiple sensors and it all went crazy. Got it to my garage, wiped off all the ice and it was fine after that. The only thing I can come up with your issue is either something is blocking the sensor or it is a sensor malfunction/damage.
If you are able to replicate it all the time or easily, it would be easy to show it to the dealer so they can fix it.