Ritual Tab bug: Omen of Sinistral Necromancy does not have slot in Ritual Tab

As the title states, there is no item slot for the Omen of Sinistral Necromancy in the Ritual tab. Setting affinity to Ritual gives the error "Your Stash Tab with Ritual Affinity does not have enough space for this item." I can confirm that I have no other omens of this type. Seems like an oversight for a paid feature.

Not a bug, Ritual omens only go in the Ritual tab, Abyssal Omens do not have their own tab.

Then the bug is that the abyssal omens are classified as ritual affinity by the game.