Referencing the attached picture

Both Views (SceneView on the left, MapView on the right) have a single, multi-part polygon added to a single graphics overlay. The problem is that the MapView correctly shows the hole in the polygon, but the sceneview doesn't.
Full project attached.
Any sugguestions?
Code looks as follows:
{
var mapOL = new GraphicsOverlay();
mapOL.SceneProperties.SurfacePlacement = SurfacePlacement.Draped;
var listpc = new List<Esri.ArcGISRuntime.Geometry.PointCollection>();
var pc1 = new Esri.ArcGISRuntime.Geometry.PointCollection(SpatialReferences.Wgs84);
pc1.Add(-5, -5, 10);
pc1.Add(5, -5, 10);
pc1.Add(5, 5, 10);
pc1.Add(-5, 5, 10);
listpc.Add(pc1);
var pc2 = new Esri.ArcGISRuntime.Geometry.PointCollection(SpatialReferences.Wgs84);
pc2.Add(-2, -2, 10);
pc2.Add(2, -2, 10);
pc2.Add(2, 2, 10);
pc2.Add(-2, 2, 10);
listpc.Add(pc2);
var poly1 = new Polygon(listpc);
var g1 = new Graphic(poly1, new SimpleFillSymbol() { Color = Colors.Red, Outline = new SimpleLineSymbol() { Color = Colors.Black, Width = 2, Style = SimpleLineSymbolStyle.Solid }, Style = SimpleFillSymbolStyle.Null }) { ZIndex = 2 };
mapOL.Graphics.Add(g1);
var poly2 = new Polygon(listpc);
var g2 = new Graphic(poly1, new SimpleFillSymbol() { Color = Colors.Red, Outline = new SimpleLineSymbol() { Color = Colors.Transparent, Width = 0, Style = SimpleLineSymbolStyle.Null }, Style = SimpleFillSymbolStyle.Solid }) { ZIndex = 1 };
mapOL.Graphics.Add(g2);
_mapgraphicsOverlays.Clear();
_mapgraphicsOverlays.Add(mapOL);
}