Solid Difference not working correctly

Hi There, 

I am trying to solid difference a simple Brep and a Morph however it appears to be playing up.

Here is the Rhino window

as you can see only part of the hex chain was been subtracted. I left the prism visible to highlight the issue.

Here is the Definition of the prism

and Here is the Definition for the morph

This Operation has worked in a previous file and was just curious as to some suggestions why it may be playing up.

Cheers!