You updated the Cornerstone to the latest version (3.0.4) but not your X Theme (4.6.1). You need to update the X to the latest version (6.0.4) as well to avoid incompatibility issues.
Updating Your Themes and Plugins
Remember to clear all caches (plugin, server-side, CDN, and browser's cache) after updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Hope it helps,