If your auto Stop/Start was working then the battery was properly charged. The auto Stop/Start does not work when the battery is not properly charged. Did you test your battery and is it above 12.6 and 13v? I tend to agree that it may be water some where in the electrical system (just because it happened after the car wash) or fuel supply.when you disconnect car from battery, this appears then goes away. Reached out to Auto Fanatic. He also experienced shutdown issues with his QV, but in his case while driving on a highway, which is scary ..
I had auto stop/start just because I was almost home and low on fuel. I only drive in Race mode but when low on fuel, I switch to eco and enable start/stop. When this happened, I had start/stop enabled. I wonder if I didn't would car shutdown as well.
As far as tow, trust me Im counting my lucky stars I didn't have to use it. Thats why I kept on trying to start the car while waiting. Last thing I want is to have this car f-ed up while getting on a flat bed.