Ive noticed this especially in the Zoltun Kulle encounter, when fighting him and his 2 adds.
i have frenzy on my left mouse button skill so its my primary attack.. and when i stay with my mouse hovered over Kulle, it can never target him other abilitys seem to lock on target but frenzy does not. so it makes it difficult to single target something to kill it.
its very frustrating that i cant use this skill to burn a single target down when theres a group of enemy's.
Is this working as intended? I think its a bug ....