Thanks for asking.
Looks like you have updated Cornerstone and using latest version of the same 3.2.3. However, version of X Theme you are using is old and incompatible with Cornerstone version that's there on the website. Please update X Theme to the most recent version.
To update X Theme please take a look at following resources:
Version compatibility guide: To learn about the latest and compatible versions of bundled and supported plugins, please take a look at following doc:
2. Theme Update guide: Please take a look at following article to update Cornerstone.
3. Please take a look at following doc about changelog:
_After doing the updates, always remember to clear all caches (if you are using WP Rocket, WP SuperCache or W3 Total Cache) when updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.-