I'd say Napoleon is "pushing the envelope" for continued sexual behaviors after neutering. How old was he was operated on?I just read that in many animal species,the later males are neutered the more likely they will continue their sexual behaviors becausethe behaviorshas become so imprinted.
You did say, "occasionally," so maybe that infers a diminishment, eh?In which case, he would be reacting along a normal curve.Urinating in front of the cage may not go away because it is not necessarily a sexually induced behavior.Could be territorial or insult.Rabbits do insult one another in that manner.
Had two bucks who would regularly trade such an insult whenever either of them was released from his own cage.Immediate beeline for the other's cage and take a pee/poop.It was just a given. LOL
Buck