The brake pedal pivot bolt nut loosened itself and came off of the bolt, allowing the bolt to back out of the pedal mount and the brake pedal fell out of position and became lodged behind the accelerator pedal. Thankfully no accident occurred. After performing research with local dealer and independent repair shop it was found to be an obvious repeat failure of the General Motors safety recall #20760E already performed on the vehicle. I reached out to GM customer support who were rude and I received no help in the matter. Can provide more information upon request.