just recently noticed this - in v11 with the configurable bottom toolbar, if you normally drive by yourself and have climate control set up not-split, there is the previously mentioned empty/dead space towards the right where you'd otherwise see the passenger temp setting in dual/split-mode.
however if a passenger is sitting in the right seat, the passenger temp setting now appears there automatically when the car is is D or R, regardless of the split setting. Goes away again when passenger gets out of the seat. btw not unique to MS, I noticed same in a friend's MY