Hate confusion is a passive skill that certain special BOSSes have, which causes their hate value to become chaotic when their Vitality Points drop to a certain level, randomizing targets among the enemies that deal damage to them!
When hunting a BOSS as a team, the most troublesome scenario is encountering this situation. A Main Tank usually holds the BOSS's aggro firmly, but once hate confusion is triggered, the BOSS will abandon the attack on the MT and choose to attack other players, especially troublesome if it targets ranged or healing classes—for the team, it's nothing short of a disaster!
Hunting a BOSS with "hate confusion" skill not only requires team strength but also a great deal of luck!