On June 29, 2022 My 2022 Nissan Frontier was parked drive in front of garage door. I arrived home for lunch and parked my cab farm tractor in yard under shade tree to keep cool while I was inside my home. When I came back to leave my tractor had Frontier truck sitting against front tire of my tractor, the truck had moved 25 yards for no reason. The truck had made slight contact with tractor bumper with tail light lense laying in yard, the trailer ball had also struck tractor tire and prevented hard impact. I went in garage and obtained key fob and found truck still in park. I tested truck and all functions were normal as they were 6 weeks ago when I purchased new. Key was not in truck and no one else had access in the 15 minutes I was inside. The parking brake was not used by wife when she parked, but it was in park. Mileage was 2550 . I someone had been standing between the two vehicles they could have been rolled over. I'm out over 500 bucks for tail light, I checked vin number, was advised no recalls. Wife is learning to use parking brake.