matrixoutput for gl objects before returning to gl

Robbie's icon

I am confused about gl objects when they output a matrix. I want to convert gl into a matrix to use with other matrix-based objects then pipe it back into a gl render context but weird results occur.

What happens to the jit.gl.nurbs in this below example? Is it a problem with the number of planes and type in a jit.gl.nurbs object?

Max Patch
Copy patch and select New From Clipboard in Max.

many thanks in advance