Here's what we consider a rendering bug in LayOut:
If you export a 2D png in SketchUp, your raster-rendered model in LayOut should match.
If you export PDF in SketchUp, your vector or hybrid-rendered model in LayOut should match.
But it sounds like you're describing an unsaved style in a a scene that isn't updated. Save the style first, then save the scene.
b
ps - whenever I say that, it reminds me of the TV show Heroes: "Save the Cheerleader, Save the World".