I'm not sure if this is a Bug or not but the Tudor spiral stairs are not stacking. as a spiral usually stack on top of each other allowing for compact stairs to give multiple levels they do not go beyond one floor. if this is not a bug can you please allow this, the other stairs are to big.
I used these in the previous build, stacked one on top of the other to create a multiple-level spiral staircase.
This is no longer possible.
Doing some testing, it looks like these require a floor/foundation below them and another set of spiral stairs isn't satisfying this condition.
Adding column/s on the 'corners' of the cube that the stairs occupy isn't enough to satisfy the support requirement, either.