Ninja Gear Enchant

Inside the Amatsu Ninja Guild (que_ng), the NPC who does gear enchants (Artisan Tene @ 75, 20) claims that he enchants the 3rd and 4th slots of a one-handed weapon in your right hand. However, when I try to enchant my Mikatsuki, it only enchants the 3rd slot. He refuses to enchant the 4th slot even if you offer to pay him again, despite the fact that he told you he would be enchanting both slots the first time around. The dialogue is also kind of weird (he says he's enchanting the 4th slot when he's enchanting the 3rd slot).

Not sure if there are issues with enchanting other weapons/gear as well.