I can't find a way to notify a bug, so here it is as an improvement proposal:
When I plan a drive on the phone before plugin the phone to the car, I don't get anymore alerts and display of speed in Android Auto.
If Waze is off on the phone when I connect to the car, and I start the itinerary in Android Auto, everything is fine.
I connect using USB-C cable, and phone is Fairphone 3 with Android 10, but I saw it on other phone brands as well