My balance wizard was fighting Red Claw Informants in Grizzleheim, and used a 5-pip Justice with 10% damage boost, just enough to kill one at 550 health. However, though the death animation played and the informant disappeared, it remained on the battlefield with 1 health, and I had to use another spell to finish it off. Dealing overkill damage seems to work just fine, so I think it's either an issue with damage boosts or just the damage boost stat itself.
