Ubermenu uses the Font Awesome to show that kind of arrows and stuff. The homepage does not have any problems, but the portfolio page throws the error below on my browser console:
/portfolio/#AccordionBook:1 Access to Font at '.../wp-content/plugins/ubermenu/assets/css/fontawesome/fonts/fontawesome-webfont.woff?v=4.7.0' from origin '-' has been --blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '-' is t--herefore not allowed access.
The error is about the CORS policy on your server which you can fix following the steps below: