On Ubuntu 18.04, some PDF documents repaired/cleaned by pdftocairo (version 0.62.0) during
Driverless Printed PDF Processing produce errors when printed with CUPS: rendering on paper is wrong or incomplete. Same action on Ubuntu 16.04 with pdftocairo version 0.41.0 works fine. I reported this as Poppler Issue 897. A workaround is described at SavaPage Issue 1113.
On Ubuntu 19.10, pdftocairo version 0.80.0 works fine. Thus, the issue has been resolved in a more recent version than 0.62.0. It is unknown in which version that was exactly.