CDN Problem / Fontawesome Problem

Dear Members,

I really love the job board theme but i have now a new problem. If I turn the CDN on (for example with WR-Rocket or WP Super Cache) then I dont see any Fontawesome icons more . Are the hardcoded into CSS ?

How can I fix the icons? It makes no difference what CDN I use (MaxCDN or KeyCDN). I get no icons.

Something about this:
https://docs.wp-rocket.me/article/24-resolving-issue-with-cdn-and-fonts-icons
https://stackoverflow.com/questions/22002238/font-awesome-icons-not-rendering-via-the-boostrapcdn

Thanks for any help..
Andy