Stair not solving correctly

Hello, I ran into a strange issue. I am trying to have a stair with 1 step centered between two landings, but if I add the control points, somehow the solver removes the last step (on the right the natural solver, on the left the one I am trying, as you can see the second one is shorter):

Hi @XDGA please send us this 3dm file and we will take a closer look. (visualarq@asuni.com)