When updating X, kindly also make sure to update Cornerstone and Visual Composer to the latest supported version. Here is a link for a details information on how to do an update:
Please remember to clear all caches when updating so that the code from the latest release is always in use. This will help you to avoid any potential errors or any unexpected display issue on the site.
Once you have updated visual composer, please make sure you have to toggle on the X legacy integration (make sure not to edit and save anything if the integration is still inactive, else visual composer will automatically wrap them with text shortcodes).