Driving home today my 2004 Limited (Nav) changed channels on its own multiple times. I had a 2 hour drive, was listening to an AM talk show and could not figure out what was going on. Every now and then it would change up or down for no reason. I was on 560 and it would jump to 550 or 570. I was navigating and had the Nav screen up, if that makes a difference. Has anyone had this happen?

Does anyone have any thoughts on what happened?