It was reported here: http://fofou.appspot.com/sumatrapdf/topic?id=879322 A PDF from http://www.mediafire.com/?br10bonn801mev3 is mis-rendered. It looks much better than when using mupdf code from the past, but with mupdf trunk as of today (8/7/2010) it still has rendering issues when compared to Adobe, especially on the last page.
Created attachment 6630 [details] pdf that is misrendered Attaching PDF in case the original goes away.
The attached document looks much better if the incompatible Indexed colorspace is simply ignored (cf. http://code.google.com/p/sumatrapdf/source/detail?r=2761 ).
Ignoring the indexed colorspace makes the page readable, but the effect from the softmasks is inverted. I tried hardcoding the 0 (black) value to be transparent when expanding the indexed pixmap and then it looks almost correct. This is the same area that should be masked out in image 135 with the softmask image 147. This mask was simply not copied over when expanding the indexed pixmap to full color!