I worked in a Ford dealership for over 10 years as a service tech. and have seen your concern several times. coolant leaks when hot and "fix" it's self after a cool down period. This is generaly caused by a weak or cracked hose clamp (Ford uses the spring clamp style) also often times it is also caused by the clamp retainer left on (a "U" shaped peice of metal that holds the clamp in a compressed state during assembly). Inspect all clamps, often if the clamp is cracked it will break if compressed. this condition is not normal and you should bring the vehicle back to the dealership for service. Your vechicle is still in it's "break-in period" so the last thing you would want is your FEH to overheat.