With the release of Kirki version 4.1, we have added a settings page that allows users to clear their font cache.
Clearing the cache will remove the local fonts folder located in the wp-content -> fonts directory and force a re-download of the Google fonts.
This can be useful in situations where, for example, a site has been moved to a different server or its domain name has changed, and the fonts are not displaying correctly on the front end of the site.