I purchased a very low mileage 2008 Prius this summer. Lately, I have noticed that it is changing radio stations on its own. At first I thought maybe I accidentally touched something else and I let it go. It also will jump from FM to AM and from FM1 to FM2. I finally realized that it was not me when I turned the corner with both of my hands firmly on the wheel and it jumped. Any ideas or solutions? This happens at least once a day.
I suggest posting in the Gen II Audio and Electronics section. There are many tales of woe there about radio buttons that stop working but I dont recall anyone posting with symptoms similar to yours. But you never know - someone may have had this happen and can give you some advice. Good luck!