Create Block removes surfaces in shaded viewport

As titled, when I create a block it removes shading from some surfaces in the shaded viewport. The other viewports such as render work normaly. I see there are a couple related threads but not in the create block command.


i guess this is a bug that the creation of the block causes the display of the block contents to be single sided. Before creating the block you might use the _Dir command and Flip to make sure the surface normals are pointing outward until this is fixed.