Thank you for writing in, you updated Cornerstone to the latest version (3.4.6), but you leave X theme behind (6.3.8). Please update your X theme to the latest version (6.4.6).
Updating Your Themes and Plugins
Remember to clear all your caching features (plugin, autoptimize, 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.
Let us know how it goes,