Sounds like a blend door is not closing There are calibration tests that can be performed on the HVAC system to determine where the fault is. May require a simple recalibration of the HVAC system, a software flash, or possibly a blend door actuator. Diagnosis and repair for this concern should not be difficult. Should still be under warranty as long as the mileage is under 36K. No service bulletins or STAR cases that I can see.