Unarmed Weapon Mastery on an archer

[Micteu]

When Amber hit level 9, she got her first level of Elemental Archer: Air. I also took Improved Rapid Shot. I don't know if either of these did it, but for some reason now when she unequips her crossbow, Unarmed Weapon Mastery enables, despite not having the feat. Then, when she equips the crossbow, it stays on. It does seem to go away if she switches weapons, though.