If you attended Shapeways Live Yesterday, you heard about a Render update on the site. This fixed a lot of stuff in the background that you'll not notice, but it did fix one thing that you should appreciate. Previously, color renders were limited in the number of colors displayed. This caused the render to not appear properly. Not good if your relying on that to see how your model will look when printed. Note that this fix is for the static image and not for the 3D render (in the works). So before you would have seen something like this To this! Look at that blue water and grey poptart cat!
Will this also fix the vertex color models? Like this one https://www.shapeways.com/model/659848/ it has been "rendering" for quite some weeks now And dang missed the Live, will have to watch later. https://www.ustream.tv/recorded/26175875
Right now, you'll have to reupload the model to take advantage of the update. Worth a shot to see if it fixed it.