QPdfWriter and cosmetic pens of width 0

Starting with Qt 5.12 the handling of cosmetic pens with a width of 0 has changed.
Attached you find the output of some PDF files being created with the bode example of the Qwt library ( qwt.sf.net ).

Using a pen width of 1 is no equivalent workaround as it results in a document, where the line gets scaled ( becoming fat, when zooming in ) inside the PDF viewer ( using evince here ). So it seems, that the desired output is not doable since Qt 5.12.

Actually I would like to be able to make pens with a width > 0 being cosmetic for the viewer like it is possible with Qt 5.11 and a width of 0. IIRC this was never possible with Qt, but is actually what someone needs, when analyzing a plot inside a PDF viewer.