Shaper seed anoint on Merc stops him cursing

I have a merc (Cruel Mistress)

Despair, Void Sphere, Voltaxic Burst Profane Cascade, Envy, Zealotry.

I have 2 shapers seed amulets, one has the last rites anoint the other one doesn't.

With the amulet with the anoint, he stops casting his curse. The anointless amulet lets him curse.