Upon further investigation, it seems that their font for Rubik is corrupt or otherwise problematic. Converting to ttf gives the same results. The font can be viewed on Windows, but the behavior in the browser (FF56.0b2) is the same.
Browsers that seem to display it can do what I had using a backup system that looks similar.
This is the problem at their end, as the problem is with the font file, not with the stylesheet, as I originally stated in this answer.
I converted woff to ttf using the Google woff2 tool , then tried the ttf version locally, without unicode-range and the results are the same. Here is a preliminary version of the truetype version of the font converted from the woff2 version to FontForge if someone wants to see if the glyph is in the right place (note that this version of the font also doesnβt work in the browser):
![! [truetype font glyphs] (http://imgur.com/a/Ztx7c)](https://fooobar.com//img/69014f51cceeebde22d4e024fd683199.png)
source share