Stair and wall SEO issue

[toastish]

Hi all! I'm having an issue with a stair that has a wall on its boundary that is cropped with the stair as the operator with upward extrusion. I would like for the line appearing at the end of the first flight at the bottom of the landing to be gone. This is not the first time this has happened and I would like to know if there is a fix to this problem.

[max_min]

Is that middle landing a separate slab? Its likely this could be an interaction between the 3 elements. Just for testing purposes move that middle slab up so that its no longer touching wall or stair to see if the line goes away. If it does, then its definitely an issue between the 3 intersections. If thats the case; try splitting the wall so that it stops when the stair element stops, and then you do SEO with left segment of wall and Stair, and a second SEO with right segment of wall and slab.