I checked my test site and the builders' UI icons are there.
This must be unique to your WordPress and / or server setup. Please check
Ensure everything is up to date. Please follow the best practices when updating your theme and plugins. See https://theme.co/apex/forum/t/setup-updating-your-themes-and-plugins/62 for more details.
Clear all caches including browser cache then deactivate your caching plugins and other optimization plugins.
If you're using a CDN, please clear the CDN's cache and disable optimization services.
Test for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it's fixed, you'll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
If you have browser extensions, please deactivate them all temporarily.
If nothing helps, please provide us with WP Admin and FTP access in a Secure Note.