When you switch the engine off it stops burning fuel so there is no further waste heat produced. Overhaul the temperature of engine will drop from this point although certain localised parts may increase in temperature slightly for a limited time due to conduction from adjacent hotter parts and without the benefit of the convective cooling of motion.
Areas were this might be undesirable are metal fuel lines with consequent vaporisation of fuel within, leading to poor re-starting. I can see no likelihood, and have no experience of this happening on the X-Wedge though.
