Renderworks - Clip Cube showing ghost walls in render.

[newo]

I'm currently creating some renderworks styles to use.

The renders that I create are usually with clip cubes with more of an orthogonal view. For some of the styles I want to have artistic edges applied; but whenever I turn them on, the renders start showing the section cuts of the back walls that the clip cube is cutting through as transparent. These clip cube section cuts appear over the 3D renderings and look like random transparent objects. How do I stop this from happening? 

[newo]

See left side of render.