Strange how things vary. Those screenshots do come from a LM 17.1 admittedly not updated for some time and MATE DE I would not have thought that a Cinnamon version would be much different.
Have a look in ~/.config/fontconfig/conf.d/ for the file 78-Reject.conf file generated by Font-Manager. I will attach the one from that LM 17 installation for comparison, it might show some difference.
Have a look in ~/.config/fontconfig/conf.d/ for the file 78-Reject.conf file generated by Font-Manager. I will attach the one from that LM 17 installation for comparison, it might show some difference.