Displaypipe Problem. Two components can not be shown together

I have implemented using the displaypipe method to display, but I found that two modules cannot be displayed simultaneously. If they are separated, they can be displayed separately.
But what I need is to display both modules simultaneously



One of the methods is as follows:

  public override void DrawViewportWires(IGH_PreviewArgs args)
  {

    Plane plane;
    args.Viewport.GetFrustumFarPlane(out plane);
    Color col = new Color();
    for( int i = 0;i < _curves.Count;i++)
    {
      double ppu;
      args.Viewport.GetWorldToScreenScale(pts[i], out ppu);
      plane.Origin = pts[i];
      if(grades[i] == 1)
        col = Color.DarkBlue;
      if(grades[i] == 2)
        col = Color.FromArgb(51, 112, 204);
      if(grades[i] == 3)
        col = Color.Green;
      if(grades[i] == 4)
        col = Color.Yellow;
      if(grades[i] == 5)
        col = Color.Orange;
      if(grades[i] == 6)
        col = Color.DarkRed;
      if(views)
      {
        args.Display.Draw3dText(grades[i].ToString(), Color.White, plane, 10 / ppu, "Arial", false, false, Rhino.DocObjects.TextHorizontalAlignment.Center, Rhino.DocObjects.TextVerticalAlignment.Bottom);
      }
      args.Display.DrawCurve(_curves[i], col, 2);
    }

  }