2. Download PDF before printing
If you are not able to install a recent Firefox Beta release on your machine, please work around the problem by downloading the PDF documents before printing, e.g. by using the bulk download option as outlined on Auswahl an Druckschriften-PDFs herunterladen.
Firefox 66 is around the corner and the problem will most likely go away by simply upgrading.
Please enjoy your research and sorry for the inconveniences this might cause to you and your colleagues.