I found out that oath keepers dont work with the heavy ammo exotic bow Leviathans Breath. The exotic works fine with other exotic/none exotic bows. I have tested the new archetype of bow and it also works so im incined to bellieve that it is specifically related to the Leviathans breath. Thanks for reading and potentialy helping. correction it increases the dmg of the bow by 10dmg from 1090 to 1100