found this via the search - it indeed is the fix for sporadic unexplained ac activation - once "off", the hvac controls do what one expects them to do. thank youThere's also a setting for turning off the auto defog. Only thing I can think of that would override your manual control.
p.186 2017 manual:
Auto Defog : The system will monitor high humidity inside the vehicle. When high humidity is detected, the climate control system may adjust to outside air supply and turn on the air conditioner or the heater. The fan speed may slightly increase to help prevent fogging. When high humidity is no longer detected, the system will return to its prior operation. To turn Auto Defog off or on, see “Climate and Air Quality” under Vehicle Personalization