I haven't experience the auto rear breaking feature so far... Maybe try driving down your inclined driveway slower to see if it will not trigger the auto braking?
My auto braking has work perfectly so far. The best example was its pedestrian detection. I was driving on the interstate in the rightmost lane, and there was a trailer truck in front of me. I noticed there was a work area ahead in the breakdown lane, and traffic start moving over a lane to the left. I started slowing down, signaled to move left, and waited for the chance to move over. The trailer truck in front of me moved over a lane which exposed the safety flagger on the edge of the road, almost into the travel lane, waving traffic to slow down. As soon as my car detected the flagger on the edge of the road, my car started auto braking. In my opinion it worked perfect for this circumstance. I captured a video of it on my dashcam for review.