We've released a new version of the Roundcube Plus skins that fix problems with loading Google fonts under the latest version of cPanel. If you noticed that your skin's fonts don't look right under your cPanel installation, you should upgrade to fix the problem. cPanel filters the css files before serving them and removes all double slashes, which causes problems when importing remote content.
cPanel changes the font urls from this:
With a single instead of a double slash after https, the font won't load properly. The upgraded versions of the skins that fix this problem are available for download in our customer area.