Q: AC thermostat stop working each time the light on the AC button start blinking.

I changed my compressor in December last year barely 3 months now. Recently, I notice that the air is not blowing as it should be, so I took it to my mechanic who confirms that the compressor is still in d good state and that the air had reduce in the compressor, so he refilled the air. As I left his place, the AC light started blinking and immediately trip off thermostat as such stop the flow of air. He seems not to know the cause of it. I notice that when the has rested for some time and the engine switch on, the ac will working comfortable for about 10-15 mins before the light will start to blink and after that it won't stable again (ac thermostat stop working) until the car engine will be switch off and rested for another long hours. Please what could be the problem? Some are suggesting compressor clutch. Please I need your help so I won't end up touching what I ought not to have temper with. Thank you.

My car has 126124 miles.
My car has an automatic transmission.