SplitCyclical IndexOutOfRangeException

[dsn27]

Customer reports this error that can occur sometimes.
No repro available yet.

Exception Source: CADability
Exception Type: System.IndexOutOfRangeException
Exception Message: Der Index war außerhalb des Arraybereichs.
Exception Target Site: SplitCyclical

---- Stack Trace ----
   CADability.Shapes.Border.SplitCyclical(positions As Double[])
       Border.cs: line 2081, col 21
   CADability.Shapes.Border.ConvexHull()
       Border.cs: line 4354, col 29
   CADability.Shapes.Border.GetSmallestEnclosingRectangle()
       Border.cs: line 4410, col 13
   LogiCal.CADModule.Calculation.CadHole.ProcessBorder(border As Border)
       CadHole.cs: line 0073, col 13
   LogiCal.CADModule.Calculation.CadItem.ProcessHoles(simple As SimpleShape)
       CadItem.cs: line 0543, col 17
   LogiCal.CADModule.Calculation.CadItem.ProcessSimpleShape(simple As SimpleShape)
       CadItem.cs: line 0403, col 13
   LogiCal.CADModule.Calculation.CadItemCollection.ProcessSingleMode(cshape As CompoundShape)
       CadItemCollection.cs: line 0342, col 17
   LogiCal.CADModule.Calculation.CadItemCollection.ProcessCompoundShape(totalCalcMode As Boolean, cshape As CompoundShape)
       CadItemCollection.cs: line 0143, col 13
   LogiCal.CADModule.Calculation.Calculator.ProcessGeoObjects(totalCalcMode As Boolean, geos As GeoObjectList, data As DefaultData, progress As IProgress`1, ct As CancellationToken)
       Calculator.cs: line 0325, col 13
   LogiCal.CADModule.Calculation.Calculator.ProcessFrame(totalCalcMode As Boolean, geoObjects As GeoObjectList, data As DefaultData, progress As IProgress`1, ct As CancellationToken)
       Calculator.cs: line 0026, col 13
   LogiCal.CADModule.<>c__DisplayClass430_0.<StartCalculation>b__0()
       frmCAD.cs: line 0965, col 54
   System.Threading.Tasks.Task`1.InnerInvoke()
       : N 00078
   System.Threading.Tasks.Task.Execute()
       : N 00071
   System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
       : N 00032
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(task As Task)
       : N 00062
   LogiCal.CADModule.<StartCalculation>d__430.MoveNext()
       frmCAD.cs: line 0965, col 13
   System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
       : N 00032
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(task As Task)
       : N 00062
   LogiCal.CADModule.<bbiStartCalc_ItemClick>d__375.MoveNext()
       frmCAD.cs: line 0501, col 13
   System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
       : N 00032

[dsn27]

If the positions array contains:
double[] positions = { 1.7797981169118655, -1.9057885098560976E-15)

The second itaration of the for loop will fail with: IndexOutOfRange Exception.
Because the index equals -1

The attached DXF file was used to reproduce the problem in our software. But I haven't been able to create code for CADability to make it fail.
IOOR.zip

[dsn27]

Load DXF file from above and run code in button1_Click(...)

Code for reproduction:

        private void button1_Click(object sender, EventArgs e)
        {
            var allObjects = cadControl.CadFrame.ActiveView.Model.AllObjects;
            allObjects.DecomposeAll();
            GeoObjectList geoList2D = Create2DCurves(allObjects);
            var curve2DData = GeoListToCurve2DArray(geoList2D);


            var cShape = CompoundShape.CreateFromList(curve2DData, 0.01d, true, out GeoObjectList deadObjects);
            var sShape = cShape.SimpleShapes[0];
            SmallestEnclosingRect ser = sShape.Outline.GetSmallestEnclosingRectangle();
            Debug.WriteLine(ser.Height + "x" + ser.Width);
        }

        public static GeoObjectList Create2DCurves(GeoObjectList list)
        {
            ICurve ICGo;
            ICurve2D IC2DGo;
            IGeoObject GoNew;

            GeoObjectList golNew = new GeoObjectList(list.Count);

            foreach (IGeoObject gi in list)
            {
                //Projektion in 2D und wiederherstellung des GeoObjects
                ICGo = gi as ICurve;
                if (ICGo != null)
                {
                    IC2DGo = ICGo.GetProjectedCurve(Plane.XYPlane);
                    GoNew = IC2DGo.MakeGeoObject(Plane.XYPlane);
                    GoNew.UserData.Add(gi.UserData);
                    GoNew.CopyAttributes(gi);
                    golNew.Add(GoNew);
                }
                else
                {
                    golNew.Add(gi);
                }
            }

            return golNew;
        }

        public static ICurve2D[] GeoListToCurve2DArray(GeoObjectList list)
        {
            //Convert ICurve to ICurve2D
            List<ICurve2D> curves2d = new List<ICurve2D>(list.Count);

            foreach (IGeoObject g in list)
            {
                if (g is ICurve c)
                {
                    //Project curve to right plane
                    ICurve2D curve2D = c.GetProjectedCurve(Plane.XYPlane);
                    curves2d.Add(curve2D);
                }
            }

            return curves2d.ToArray();
        }

[dsn27]

Works like a charm. Thanks!