I’d have to see screenshots from all your trees, passives, and uniques before I can look into this but I assume you have the Icarian Poison node, which is supposed to ramp up how quickly poison (or in this case armor shred) is applied.
There’s additionally a bug that is causing Aura of Decay to apply ailments (poison/armor shred) too quickly. This will be resolved in 0.7.7e.
It doesn’t ramp up as quickly if you never enter Reaper Form? That’s certainly odd, but I didn’t understand that was the case from your initial post.
Sorry for the late reply. If you’re re-casting Aura of Decay, it makes sense for it to never ramp up. Aura of Decay is toggled, so when you cast it no ailments are applied until the cooldown is finished and you cast it again. This also resets the duration Aura of Decay is active for, which means it will apply much slower than otherwise.
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