When rendering a VRML file with an Extrusion node there is a rendering error if the 'endCap' is set to TRUE and 'beginCap' is set to FALSE. The attached file illustrates the rendering. The end cap is not drawn and spurious triangles result.
Note that if both 'beginCap' and 'endCap' are set to TRUE then both end caps are drawn correctly. If 'beginCap' is TRUE and 'endCap' is FALSE then again the rendering is correct.