It will more than likely be a hydraulic issue, so swopping out the slave cyl may fix it.
Fresh high temp fluid and a braided clutch line would also be advised.
Occasionally the master cyl requires replacing.
Worst case scenario is gearbox out for a clutch inspection, however as it is temperature related then I would expect it to be a slave failure.
As the car will be under warranty then all required parts should be replaced free of charge, however if you get stuck, just give me a shout as I have ALL the above parts in stock.
Alex.