Ignoring some elites

Hey, i came across a problem with my demonbuddy ignoring "purple" elites. The blue chaps and yellow elites, he goes crazy and want to kill them all. but purple, if they are in his path of shooting or attacking other mobs they may die, but he wont engage them. Noticing this problem on bounties when he needs to kill a speciall purple elite, most noticable on "Clear the Cave of Burrowing Horror" the purple worm.



Thanks

Ignoring some elites