Transmission slams back in P when door is open

So my GF was driving in reverse but she didn't notice the driver door was open, then she started backing up and Boom! transmission slammed in P automatically, at first I though she hit something, so I got out to check the rear bumper and nothing so I was really confused ....until I found out in the manual:

"P is engaged if the driver's safety belt is unbuckled and the driver's door is opened while the vehicle is stationary and transmission position R or D is engaged. Before leaving the vehicle, ensure that the transmission position P is engaged; otherwise, the vehicle may begin to roll."

anyone one has experienced this too????

Yep. That's happened to me when I've jumped in and needed to move the car a foot or two which I would have always just done with the door open. Not any more though. It's quite a slam!

IDK if anyone else would do this as we drive with seat belts on and doors closed this isn't a Dixie jeep from the Dukes of Hazards lol. Btw Im wondering if that can harm the tranny slamming in like that?

the car will engage the parking break and shift into park if there is no weight present on the drivers seat and if the door was open. Were you leaning out or not sitting on it completely?

I was Armoralling the tires and was leaning out looking at the rear tire while backing up so I could rotate see when the wheel rotated half way around to do the bottoms of the side wall. Car wasn't happy about this technique

in my case my GF didn't close the door properly we just heard the big slam....I wonder if affects the transmission!!

So guess no soft close,tried it on mine , left the door open and all that happend was parking brake engaged and car went into park, the jerk or bang mabey was just the sudden stop from parking brake, I did not have a bang or anything , smooth but quick stop and set into P