Bug Report ID: #1697418856 'Feral Kin' Monsters invulnerable during Ritual

When doing Ritual, i encountered regular 'Feral Kin' monsters that were invulnerable. They were regular monsters. The only thing i could inflict on them was withering debuff, their hp didnt move at all.

As there seem to be a maximum count for monster spawn in ritual, it slowed the ritual considerably. Once i finished killing all the other monsters, i had to log out to exit the endless ritual event, because of the invulnerable monsters.
Sorry this time i didnt clip a screen.

It happened on the 3rd and 4th ritual of the same map, on the same monsters (they were 4). My guess would be they were 'Minions' with their rare having the periodically immune affix, but i don't have a screen to check, sorry.

Edit: someone on global chat had the exact same issue with Feral Kin, so it might be bound to this specific monster type!

Have a nice day :)