I guess that was temporary...
The issue has reemerged. I've made sure my about:config settings allow custom fonts, the advanced content settings in Firefox have been double checked to allow custom fonts to download. I've tried it with a clean profile both on this computer and another. I've disabled all extensions and nothing seems to work. It appears only webkit enabled browsers show it correctly. This is Firefox 27.
Edit: It appears Ruben was having issues a few months ago like I am on FF 25. Not sure if he's still experiencing the same issues.
Edit 2: And now they're back. This is really, really, really strange. They go away for a few hours then come back.