Ominous vault can be eaten by a chamber addon.

I’d assume thats whats happening here, as a trial chamber I came across has generated with 2 “Chamber 1” type combat chambers, both of which have generated with a “Full Corner Column” addon, niether of which have had an ominous vault. Attatched is the room with the addon, and where the vault would be had the room not had the addon. This is pretty awful after clearing out multiple combat rooms I get 0 vaults. . .