Official comment
I've used Pioneer DJ gear in temps as low as -40ºC -- it wasn't pretty, but so long as you don't allow any condensation build-up, it may still work! The worst was the headphone coil being rigid and not flexible as we're used to!
Unfortunately it sounds like some components may have suffered from the temperature swings - my recommendation would be for you to contact Pioneer DJ technical support in your region to have your XDJ-RX inspected and/or serviced.