The attached file renders incorrectly except at 72dpi; at other resolutions, there are different results that get worse as the resolution gets higher. For shading types 2 and 3, this effect happens only in the 1.8 versions, not in the 2.0 version. For shading types 4 and up, it happens in both 1.8 and 2.0.
The reason is that the transformation is incomplete if the ctm is null.
I found the file here and it was created by Matthias Kramm: