First welcome aboard.
The Burbs have a separate condenser in the rear for the rear air. It’s possible that the Freon has leaked out.
It is also possible the rear controls are not working properly. Not turning the ac on.
It sounds a little early for the Freon to have leaked already. I know very little about the ac systems on these but I do know you also have a separate heater core back there too. If the controls are not turning off the heater and the ac on that could be your problem.
All of this stuff is under the passenger side garnish opposite the spare tire. You have to get in there and take a look. There are some screws on the top of the tray then it slides inward I believe. Then you need to get the other covering off to look at the condenser and heater core. When the ac is turned on the condenser and all the tubing that goes to it should be cold, if not it is not turning on or needs a charge.