It doesnt matter though, it is 'lawfully aligned' with that enhancement, and 'chaotically aligned' with the other, but neither of those make it anything on the alignment chart. They simply give it two aspects magically. Sure they would normally clash, but the magic fixes that and it doesnt care. Just like making the weapon hot and cold at the same time, the magic fixes it and it doesnt care.
Really, I see no difference here. I know you would allow fire and cold on the same weapon, why not lawful and chaotic? Same thing really. Both are real 'forces', both are diametrically opposed.