Creating spirals stairs creates some sort of triangulation error by default. I don't know if this is a known issue, but just letting y'all know.
extra note:
There's also this thing where when I make a spiral stair into a brush, the internal radius isn't kept. I don't know anything about making tools or mesh creation/modeling in general, but I might just learn just to help out this tool. Y'all need all the help you can get, and I would love to help out. This tool is just too good, even in its early stages.