Dynamic Views Obscured Only When Printing

Hello All

I've been struggling with PDF'ing referenced dynamic views with in a 2D sheet file for some time now. Essentially, the referenced 3D views show OK on screed but appears to be partially obscured when I try and print. This is resolved by rasterizing the PDF but I am now at a stage where I would like to keep it as vectors. Please see the images below.

Many thanks!!!

Screen View:

Raterized PDF:

Vector PDF (obscured):