[1.1.1][win10] Nix creeper REALLY inconsistent?

I keep taking nix creeper / necro grimoire into the fight with mangle and ritual of summoning as its only spells. It’s not my only creature, it never says anything about “Your creatures are dead!”

Sometimes it triggers properly, sometimes it doesn’t and says “Creature can’t cast spell” with no explanation/name for the source, and sometimes it doesn’t trigger and says nothing about it at all.

REPRO: Use the combo I mentioned with those spells (any basic damage spell + ritual). Be sure to bring an ally so it’s not the “(Your creatures are dead!)” one instead of the actual bug.
USING PURGATORIAN: This bug doesn’t seem to happen at all. Nix creeper may be turning its trait off from death earlier than it’s supposed to inexplicably sometimes & purg prevents this?
GRAVEBORN: Seems to work as well as purgatorian, but I admittedly didn’t test it that many times.

CUTTING OUT EXTRA TEXT: Ritual is only casting once, my bad. At least NORMALLY it is…?

So I think it’s like this: Nix creeper casts a RANDOM one of its spells 3 times, not each of its spells.
EDIT: Most recent battle DID cast ritual 3 times? I’m so lost… I thought the game was getting confused because ritual kills the caster but the caster was already dead. What exactly is failing to cast then? It isn’t casting empty slots and I wasn’t losing charges or being sealed.