Sweep1 surface got reversed normals

I tried different ways to generate Sweep1 surface and this is the outcome:

1. (Rhino 4.0 SR9) Use Sweep 1 Rail tool and the surface is correctly generated -- surface normals pointing outward.

2. (Grasshopper 0.8.0052) Use Sweep1 component and the generated surface is inside out -- normals pointing inward.

3. (Grasshopper 0.8.0052) Use Rhino.Geometry.SweepOneRail class in C# component, the generated surface shares the same symptom with the Sweep1 component.

Is there anything wrong with my process? Or is it the bug with GH and Rhino.Geometry.SweepOneRail class?

Please advice, thanks!