The fix was pretty easy. When I zoomed in the two control points I figured out that they were apart from each other. Then I simply moved the lower one to the other one using point snap. Now there is a single control point at that particular area.
This is a Rhino 5 file, because I had no idea which Rhino you use. For some reason that model saved into a 13 MB file when I used “Clear analysis meshes” and “Export selected”. Then I opened it again, created a simple box, then selected your surface and used “Match object properties”. That removed its original material and object colour. Repeating “Export selected” resulted into a 223 kb file:
BadRamp fixed.3dm (223.1 KB)