Hatchback/liftgate Support Device problems of the 2019 Ford Expedition

The vehicle is equipped with an automatic liftgate activated by motion detected under the rear bumper. Three weeks ago, I was loading items into the back of the vehicle. The vehicle was parked and off with the parking brake on. My children were buckling up in the vehicle. While I was loading the last item from the bottom of the cart, the lift gate unexpected started descending. I didn't hear the warning chimes and started standing up with the item. By that point, the gate was over halfway down and struck be just below the occipital prominence of the skull. This resulted in a concussion and several missed days of work.