Automotive Air Conditioning Information Forum

Hi,
The car is Audi A4. When you first start the car, cooling is good and pressure read as following:

After some time, the low side pressure quickly builds up and the air becoms humid and warm. Pressure guages read as following:

Ambient temperature is about 35-40.
Many thanks in advance.

Is the compressor clutched engaged or disengaged when that second reading is made? I wonder if the compressor is shutting off or clutch disengaging.