Vulkoor's Cunning - Bugged?

[fieranna]

Summary

My Vulkoors Cunning (Red Fens item set) is not proccing poison on vorpal strikes.

What can I do? Am I bugged, or is the set bugged since the patch?

Detailed Info

This set consists of two items

Ring of Venom
Dexterity +3
Sneak Attack +2 to hit, +3 damage

Necklace of Venom
Proof Against Poison
False Life +10 hit points

Set Bonus
10% less threat and "powerful Vulkoorim Poison" on vorpal strikes

When I roll a 20, and that hit is confirmed as a critical (becuase it says critical in the combat log, and I see the additional damage in larger numbers) the poison doesn't trigger.

I receive no message in combat log. I have checked all logging is enabled.

There are no floating numbers for it.

The target shows no special icon.

I have tested this in PVP vs an alt, and vs NPCs in various quests. The alt suffers no ability score damage and no additional HP loss.

edit: NB this is the basic set, not the epic version