I just sent my GV80 into service to have this issue checked out because I thought this must be a defect. They said that it is the way the car is designed! I don't know about you, but that seems like a really POOR design to allow the rear AC controls to be able to adjust the other front zones! You could have kids back there, or whoever, and they may decide to blast or turn down the AC or heat of the driver? What a distraction and disturbance. Usually, it's the driver who is in the command and control of the car. The driver should be able to control the other zones, but not the other way around? They should be limited to controlling their own zone only! So while the rear can control only through their temp control, if they touch the fan button, it is simultaneously and identical in all 3 zones. Pretty poor, I think.