Why is glscene imposter not rendered fully but cut-off?

Question

I hope someone can help. I created an imposter with Delphi GLScene but it seems that the imposter is not rendered fully but that it is cut-off. The imposter is to the right in the attached image and the 3D model to the left. The funny thing is that when I created an imposter of the teapot everything work as expected. It seems that with some models I have this problem and with others I don't. The rook is a TGLFreeForm. I have played around with camera position, depth of view of the camera and scale before loading the models into TGLFreeForm but to no avail. Does anyone have an idea how I can solve this problem?

You can make an imposter of a 3d Model by using the TGLStaticImposterBuilder component. It is when a few images if the model are generated from different camera angles beforehand. Instead of rendering the 3D model, the best suited image is displayed when rendering. This improves performance drastically but consumes more memory.