unpredictable mesh generation

[BlackRainbowFT]

Hi!

I'm creating a vertical road using the generator (shape extrusion) and feeding it a a randomly generated set of control points.
The road itself is completely flat (localPosition.z is always = 0).

About 50% of the time the generated mesh is perfect (it took me a while to avoid overlapping triangles and getting z fighting) and the remaining times the road insists on behaving unexpectedly.
It all depends on what I select as Orientation under my Curvy Spline general settings: 
- if I select "Static": some parts of the mesh will be flipped 180°  (this happens 100% of the time) (picture 1).
- If I select "Dynamic": sometimes (~50%) I get what I want (picture 2) and sometimes it starts twisting around (picture 3) and when it does it's not like the road is always perpendicular to the x axis... it may start correctly aligned and then corkscrew around the Y axis...

   

this is the main loop that generates the spline:

Code:

        CurvySpline CS = RoadSpline.GetComponent<CurvySpline>();
        for (int i = 0; i < numberOfCPs; i++)
        {
            CurvySplineSegment CSS_Last = CS.ControlPoints[CS.ControlPoints.Count - 1];
            CurvySplineSegment CSS = CS.InsertAfter(CSS_Last);
            float xPosition = Random.Range(-maxHorizontalWidth, maxHorizontalWidth);
            float yPosition = CSS_Last.localPosition.y + verticalSpacingBetweenCPs;
            CSS.localPosition = new Vector3(xPosition, yPosition , 0);
            CSS.localRotation = CSS_Last.localRotation; //this doesn't help either
            

        }

any ideas?

Thank you for your help!