It only happened on the one trip so difficult from only the one time but it did what it did so there is a thresh hold to the system and in my unqualified but experienced thoughts is that the heat load it was trying to transfer out of the system from the intercooler was high enough volume to then transfer back onto the A/C condenser. If there had been water temperature gauges and sender units either side go the I/C radiator, a more definitive assumption could be made.
Even a quality engine water temperature gauge could of shown any raise in temperature from the engine radiator.
What size heat exchanger (radiator) is used in this system?