plotting poly shape with multiple regions and no holes plots some regions as holes

I converted some voronoi cells into regions in polyshape using polyshape and addboundary with the 'Simplify' == false option. When I plot the resulting polyshape that contains 38 regions and no holes, the resulting plot does not shade some of the cells making it look like there are holes. However, if I plot each region individually, it plots correctly, as shown by plotting region 9 in second figure. (This is on Intel Macbook Pro). Is this a bug?