That's standard with SC on the 718, so maybe the 991.2 is the same? On the 981 it's only in Sport+ as you know. It can't be turned off or on independently as far as I'm aware.
I was playing and found if you press PSM once, it goes to Sport, if you press and hold it goes to Off (or as off as it will go). On "Off" it does indeed let you blip yourself in Sport and Sport+ so thanks