Shadower Venomous Stab doesn't apply to mobs

Description: When attacking mobs with any skills thief have does not apply Venomous Stab dot damage or visual effect. however, attacking the training dummy does apply the dot damage and visual effect. Steps to Reproduce: Attacking mob using any skill while having points in Venomous Stab Expected Behavior: Applying the dot damage and see the visual effect Actual Behaviors No visual effect of the green smoke appears and no damage dealt