Why you think this is a problem ?
We just haven't modeled the mover vehicles ( or person, sometimes those stairs can be pushed manually ) for that kind of stair, but we assumed that having an additional stair variation model, even with no driver, is better than no variation at all, never imagined someone could see it as a problem. That kind of stair has been there in GSX since it was released, you are just seeing the better looking PBR version.