The evaporator is freezing up. Yes, like a big chunk of ice, and that does not allow the air to pass very well. Check to make sure the freeze probe is correctly installed into the evaporator fins. The unit should be cycling the compressor on and off to control the formation of ice on the fins.
OEM Auto Engineer- Embedded Software Team
09 Holiday Rambler Endeavor 41SKQ Cummins ISL
2012 Jeep Grand Cherokee Limited Toad