Radio came on while car was not on and key was not in ignition at all. Back hatch was open for groceries. Radio was at high volume and would NOT turn off with the switch. After car was started, I kept pushing on/off button and finally, it worked. How the heck can it turn on by itself when the car isn’t even on?
I have heard of this when the battery needs changing. Keep in mind none of the switches on that radio actually turn it off. They simply tell a software to turn it off and that goes a bit crazy when the battery voltage drops.