I have downloaded the PDF document from the top of this web page https://ieeexplore.ieee.org/abstract/document/7894201 (too big to attach).

When I attempt to open the PDF document with zathura, it crashes with the following log:

zathura 7894201.pdf zathura: source/fitz/colorspace.c:1399: fast_rgb_to_cmyk: Assertion `"This should never happen" == NULL' failed. Aborted (core dumped)

The document opens OK using evince.

Additional data

zathura --version zathura 0.4.0 girara 0.3.0 (runtime: 0.3.0) (plugin) cb (0.1.8) (/usr/lib64/zathura/libcb.so) (plugin) djvu (0.2.8) (/usr/lib64/zathura/libdjvu.so) (plugin) ps (0.2.6) (/usr/lib64/zathura/libps.so) (plugin) pdf-mupdf (0.3.3) (/usr/lib64/zathura/libpdf-mupdf.so)

evince --version GNOME Document Viewer 3.28.5