At least I know what this is like now. I tested it while backing up into a toy and it is incredibly abrupt and scary even at very low speed.What a fright I got!
Reversing into a space in an underground car park. All looked clear but on the turn in sudden jolt and stop! Thought I’d hit an invisible barrier but got out and...nothing.
my only deduction was maybe I was going to fast and the car reacted to the nearby adjacent car. Anyway definitely scared the hell out of me as I thought of the insurance claim🤨.