"nv" driver bug?

[Dennis Jacobfeuerborn]

When using the "nv" driver on a Geforce 2 MX the images on the following 
page do not get rendered correctly (opaque pixels get rendered white, the 
last picture on the page contains some grayscale gradient areas (alpha?)): 
http://tango-project.org/Window_Experiments
(also see https://bugzilla.mozilla.org/show_bug.cgi?id=334951 about this)

Today I replaced the card with a Radeon 9500pro using the "radeon" driver 
and the problem disappeared. Since the images display fine when using 
anything other than a current Firefox trunk build could this be a bug in 
the "nv" driver that gets exposed by the cairo version included in these 
Firefox builds?

Regards,
   Dennis