Im pretty sure you dont get it activated without touching the brake. In that case it would be something new due to higher brake regen. My current 530E pretty much stops breake regen before you stop completly to allow the car to roll freely if you wish to do so. In eco pro the breake regen wont kick in without touching the breake pedal at pretty much any speed, instead it disconnects the drivetrain from the gearbox/engine to reduce roll resistance.
Also like above post says, if you are on a steep hill going up it activates when turned on ofc, but i dont think i ever tried to "roll" to a stop without putting my foot on the breake pedal before rolling backwards with it enabled.
I pretty much dont use it though because i always roll backwards from that kind of situation into my drive way, but i press the brake to get rear view cams to turn on by going into reverse even tho i never use any throttle after switching gears..
Maybe im a bad example but if you dont want it to stop you the button is so accesable behind the e breake that i turn it on if i need it insted of off when i dont need it..😂 Maybe my memory is screwed from almost never using it when driving around and rolling backwards every day..