A/C in my VL RB30 not working like it should

[mag]

Hi guys this is a strange one, A hot day with A/C on and you pull up at the lights and while your waiting (idling) it starts to get warmer in the car the air is now warm coming out the vents....But bring the revs up to 1500rpm and you can hear on the passenger side of the car refrigerant zooshing sounds as soon as the revs pick up and goes away after a min and the air starts getting cooler again.
Also when it does this the temp goes up or maybe that's just a coincidence

Things I've done: New fan clutch hub, new thermostat, reverse flushed block + rad and new coolant, checked relays + fuses, had A/C checked for leaks and re-gassed added fluro dye.

There's probably more but can't think of it atm....

Hope someone knows what's going on