With graphics cards without Frame Buffer Object support (such as GeForce MX400) items shows wrongly.
The reason is that if there's no support for FBO (such as PBuffer or Copy) the blitting of the rendered texture onto the icon texture can't occur on the GPU (which FBO allows) but have to be done in code. However, rendering happens asynchronous, so if the copying of the render buffer occurs right after the model has been rendered, the graphics card will probably not have had time to actually perform the queued render ops.
The solution is to design a delayed rendering mechanism, where we first issue the commands to render the model, then wait a couple of frames to guarantee that it will be rendered, and finally blit the rendered texture. This will make the icon rendering a bit more complex, but is required. For cards with FBO support we can however retain the current simple blit op (which also is much faster).
I've seen this myself and I think the same issue appears even with Cg shaders active. For some reason there's problems with all kinds of icons where a shader is involved. However, there's also a second bug in that there's supposed to be prerendered icons shown for these entities but apparently my script which creates the media package doesn't correctly copy over the icons. I'll fix that in upcoming releases, and will put the current missing icons on wfut so that you'll get them when you start up Ember now.