Technical display pipeline print error


I am trying to print a viewport using the PEN visual stile and a clipping plane to cut geometry.
In the settings I have set:



Vieport in model and layout detail space on screen is correct.
But when I print the viewport as PDF on A3, the lineweights of the visual style are completely lost, and are actually inverted (the section is thinner than the linework - see below:

How can we control this ? I have tried all lineweight controls, print panel and print resolution.

ANy ideas ?

Thanks in advance