2017 SCREW. Mine does the exact same thing. Been putting up with it for a couple years now. Its not an "after washing the car" thing. Its something else. I have no idea what. Its completely random and sometimes its the driver side mirror...sometimes the passenger. Sometimes it will only go "click whir click whir click whir click whir" for a few seconds and then it stops on its own. Other times it will keep doing it until I hit the memory button. Hitting the memory button always stops it. It happens most often if I remote start the truck. It also happens most often if the truck has been sitting in the garage all night and I start it in the morning to go to work. Temperature or humidity doesn't seem to have any effect on it as this happens summer heat and humidity, or winter cold and dryness.
I keep hoping that it will do it when I'm at the dealer getting my oil changed or something but I never wanted to have the dealer tearing up my mirrors to investigate the issue only to find nothing.
If you happen to hear what the cause is, I'd love to know.