I took the liberty to test your site in Pingdom, and found that font file “fontello.woff” is loading from a different site/domain of yours (.org).
Based on my research, font issues occur only when loading it across domain. To prevent this issue, you may do one of these things:
Host the .woff and other font files in the same domain.
or
Add necessary .htaccess code in your .org site so as to allow CORS.
David Walsh’s blog has this info. https://davidwalsh.name/cdn-fonts