Strange noise Type R FK8

Hello dear community I know such remote analyses are mostly useless, but something worries me. To my “problem”: I drove a short distance in the rain to the restaurant and back again (tank at 40km remaining range). On the way back after a smaller climb, my car made funny noises from the back, somehow like a scratch or hum (almost like a tractor), similar to when the traction control rules in it. It also felt like the car blocked in the rear. So I parked the car directly and looked if I might have a plate. Negative, no plates, no signs of damage and no system message. After restarting the car the noise was also gone again. I had this problem already at -5 degrees on a mountain with lots of snow, there I thought that it was on the snow which may have been deposited between the rims (tank full or at least half full there). But when the rain was there, I can’t happen to be worried about it. Now I have a 70km return journey today and I don’t want to break the car. Does anyone know that or has an idea what the Vorrau could be.