Look, some males are just longer than others. I don't understand why everybody is so fixated on size. Before you give the poor guy a complex just let it go.
Actually, I do not see it as a developmental anomoly, but just an individual characteristic. I wouldn't worry about it unless you should repeat the pairing and see the same issue. At that time you could always go back and notify whoever purchased it that there is a 50% possibility it may be genetic. Beautiful animal BTW.