I think all AC applied on the character itself becomes dodge AC. Which is part of the unintentional reason why old Duelist which had +2 Deflection AC (read Dodge AC) was so good. That is why the stance applies it on the armor and gives in turn then +2 Armor bonus.
It is meant to be a lesser version of mage armor that you can learn and use if need be. So it is working entirely as intended.
It could be restructured to instead provide +2 Natural AC by applying it to an item in the Amulet slot (if I remember correctly) or perhaps the creature skin; and such a suggestion has its appeal. But as Tala has written it is unlikely someone takes a look on monk stances.
It is meant to be a lesser version of mage armor that you can learn and use if need be. So it is working entirely as intended.
It could be restructured to instead provide +2 Natural AC by applying it to an item in the Amulet slot (if I remember correctly) or perhaps the creature skin; and such a suggestion has its appeal. But as Tala has written it is unlikely someone takes a look on monk stances.