Flamingo nXt 5.0 Material problems

When I render in Flamingo nXt 5.0 some materials do not appear on the object they are assigned to. The properties of the object show the material being assigned to it, setting the view port to Rendered View Port shows the material assigned to it, and when changing the Current Renderer to Rhino, the material appears in the rendering. The materials would render in Flamingo nXt 5.0 early on in the model, but at some point in the process this problem appeared. I’ve tried several dozen things to resolve this, but nothing works. Any suggestions on how to get a material to appear and render to the object it is assigned to when Rhino 5.0 is using Flamingo nXt 5.0 as the Current Renderer?