geodesic curves

hi

I ham trying to make a module, right now I'm trying to find geodesic curves out of two points on a simple lofted surface. I have four of this surface. the first one I made came out perfect, but for the next three surface it creates weird curves!!! I recently started working with grasshopper and these kind of problems drives me crazy...

can anyone help me figure out why this geodesic component work with one set of points and surface and does not work with the rest?