0.9.11 Win10 - Bastion of the Void not appearing in realm list mid-story

In a personal quest to note down which monsters spawn in which 15-floor group since it seemed consistent across 3 total runs (barring the Yeti and their unique object+godshop situation), i’ve just now noticed while doing the rounds from realm 58 that the Bastion of the Void is not in my list of choosable realms, and after quite a few rolls of random realms it doesn’t seem to be showing up randomly either.