You updated the Cornerstone to the latest version (v3.3.8), but you leave your X behind (v6.2.5). Please update the X theme to the latest version as well to make sure that this is not a compatibility issue. And also make sure the Envira Gallery that is installed on your site is the latest compatible version (126.96.36.199)
Updating Your Themes and Plugins
Remember to clear all your caching features (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.
After updating and if the issue persists, please do a testing for a plugin conflict. You can do this by deactivating all third-party plugins, and seeing if the problem remains. If it's fixed, you'll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
Let us know how it goes,