NHTSA Complaint #11695972 — 2024 GMC SIERRA 1500

On October 23rd at approximately 0900-0915 hours I arrived at a friends house located at [XXX] . As I normally do, I pulled up into the driveway which has a pretty significant incline. I shifted the column shifter into park, and turned off the vehicle via the push button ignition switch. The parking brake/hill brake system automatically engaged as per normal operation. I exited the vehicle and before I could shut the door, the vehicle began to roll backwards. The driver's side door hit me in the right shoulder which pushed me to my left and caused me to roll my left ankle due to the down slope of the driver way. While I felt immense pain in my right ankle, I was able to jump back into the truck and slam on the brakes, causing both rear wheels to lock up and skid in the driveway. I then turned back on the vehicle, noting that the transmission position was still in park, and the parking brake/hill brake was still engaged. I had to disengage the push button parking brake/hill-brake, shift the vehicle from park into drive to move back up the driveway. This time I ensured that the vehicle did not move after following the exact same steps. My truck under went an approximately 30 minute software "upgrade" approximately 2.5 weeks ago. I believe there was an issue where the park sensor did not fully engage, leading the vehicle to believe it was still in an operational gear, however it does not explain how it was able to not only over-ride the parking/hill-brake itself, as well as allow me to shut the vehicle off and exit the vehicle. This safety hazard has caused me an injury that has already caused me to miss 48 hours of work (I am a federal firefighter) and will require more missed time should surgery be required. There were no warning lamps, the backup camera was not engaged, the only audible sound was the beep that the vehicle makes when engaging the parking brake automatically. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)