What weatherman said is possible if the potentiometer is damaged.
The problem is the OP reported the pedal moving on its own. There is noting in the pedal assembly that is motorized and there is no mechanical connection between the throttle pedal and the throttle body. Its all electrical. So, changing the pedal doesn't sound likely to fix anything.
I know the OP personally. He is an outstanding member of the community. I don't think anyone is question what he is reporting. If he says its happening, then its happening. The question is what the heck is doing it? Hopefully he'll get it fix and fill us in in case someone else has the same issue in the future.