Which version of Poppler are you running? The issue's been fixed in version 0.8.0. If it's not in your distro's repos as yet, install it manually from
https://poppler.freedesktop.org/
In a nutshell, issues like this keep cropping up because Onyx's software uses 'interesting' methods to produce PDFs. If you're interested in understanding what caused this specific problem (which is different from the one discussed in the earlier thread), see:
https://gitlab.freedesktop.org/poppl...ler/issues/784