Bug when drawing a box made by extruding a curve using rhinocompute

[a_shun]

Hello,
I was using rhinocompute and rhinocommon to create a box by extruding a curve, but when I drew on rhino, the box was drawn strangely.

Specifically, I created a box with the following 4 patterns.
1.extrude the curve
2.cap the brep made in 1
3.Extrude a surface on a curve
4.CreateFromLoft from two curves to create a face and extrude it
Of these, 2 and 4 were rendered incorrectly, as shown in the following pictures.
Is there any way to improve these?

using Rhino.Geometry;
using Rhino.FileIO;
using Rhino.DocObjects;
using Rhino.Compute;

namespace Extrusion_test
{
    internal class Program
    {
        static void Main(string[] args)
        {
            /// Make 3dm file
            var file = new File3dm();

            /// create layer
            ObjectAttributes attributes = new ObjectAttributes();
            file.AllLayers.Add(new Layer { Name = "1.extrude the curve" });
            file.AllLayers.Add(new Layer { Name = "2.cap the brep made in 1" });
            file.AllLayers.Add(new Layer { Name = "3.Extrude a surface on a curve" });
            file.AllLayers.Add(new Layer { Name = "4.CreateFromLoft from two curves to create a face and extrude it" });

            /// Create a curve to extrude
            Plane plane_xy = Plane.WorldXY;
            var rec = new Rectangle3d(plane_xy, 100,100);
            Curve curve = rec.ToNurbsCurve();

            /// Create a offset curve to extrude
            float offsetnum = 20;
            Point3d pt1 = new Point3d(offsetnum, offsetnum, 0);
            Point3d pt2 = new Point3d(100 - offsetnum, 100 - offsetnum, 0);
            Rectangle3d offsetrec = new Rectangle3d(plane_xy, pt1, pt2);
            Curve offset_curve = offsetrec.ToNurbsCurve();

            /// Extrude the curve in four ways
            /// Checking these drawings, 2 and 4 go wrong.
            /// 1.extrude the curve
            Surface extrudedSrf = SurfaceCompute.CreateExtrusion(curve, new Vector3d(0,0,100));
            var extruded_brep = extrudedSrf.ToBrep();
            attributes.LayerIndex = 0;
            file.Objects.AddBrep(extruded_brep, attributes);
            /// 2.cap the brep made in 1
            Brep cappedBrep = BrepCompute.CapPlanarHoles(extruded_brep, 0.01);
            cappedBrep.Transform(Transform.Translation(new Vector3d(200, 0, 0)));
            attributes.LayerIndex = 1;
            file.Objects.AddBrep(cappedBrep, attributes);
            /// 3.Extrude a surface on a curve
            var pathCurve = new LineCurve(new Point3d(0, 0, 0), new Point3d(0, 0, 100));
            Brep[] breps = BrepCompute.CreatePlanarBreps(curve);
            extruded_brep = breps[0].Faces[0].CreateExtrusion(pathCurve, true);
            extruded_brep.Transform(Transform.Translation(new Vector3d(400, 0, 0)));
            attributes.LayerIndex = 2;
            file.Objects.AddBrep(extruded_brep, attributes);
            /// 4.CreateFromLoft from two curves to create a face and extrude it
            pathCurve = new LineCurve(new Point3d(0, 0, 0), new Point3d(0, 0, 100));
            Brep[] loftSurfaces = BrepCompute.CreateFromLoft(new Curve[] { curve, offset_curve }, Point3d.Unset, Point3d.Unset, LoftType.Normal, false);
            extruded_brep = loftSurfaces[0].Faces[0].CreateExtrusion(pathCurve, true);
            extruded_brep.Transform(Transform.Translation(new Vector3d(600, 0, 0)));
            attributes.LayerIndex = 3;
            file.Objects.AddBrep(extruded_brep, attributes);

            /// Save file
            file.Write("extrusion.3dm", 6);
        }
    }
}

Any help is much appreciated

Thanks