Sometime ago there was a feature that explained how to reset the opening & closing of the heater vents .....recently the top [ middle ] two vents one is blowing hot [ left ]  side while the  [ right ]  side is blowing cold ,when set at cold on the a/c below 18 degrees ....is it advisable to leave it for the dealer to do when the last free service is due around November  & just  close that vent completely off  & let my wife suffer with the " summer heatwave " ! 

 

mines doing the same. I'll have to get the dealer to reset it again.