Consuming expired corpses doesn't work for Necrotic Potency

Grandma

So if your summoner's armor or Spirit Guardian expires from time- not resummoning - then using Necrotic potency does not give you any ultimate regeneration. I've been watching it carefully and it never increases the ult number, in combat or out. However, it still procs things like Renewing Undeath, so it's not entirely useless, but consuming it with necrotic potency consumes the corpse and gives you nothing for it.

of course necro potency works for other corpses, but not ones generated and expired by regular. a few times i've noticed it works when i resummon early and consume the still somewhat new corpse.

am i just mis-seeing this or is this a thing that I can get a response on? It's screwing with my healer build.