Your slider is working in the staging.
Cornerstone and WPEngine doesn't really go along much. The Cornerstone builder takes place on the front end, in most cases WP Engine tries to cache its resources. This can cause stale data to be loaded. To resolve this, you'll need to clear the site cache in WPEngine right after saving every changes you made in Cornerstone.
How to purge the site cache
You can use our interactive tutorial, “What should I do if I make changes and they don’t take effect?“, in the User Portal, or you can follow the instructions below.
Purging your site cache is very easy. You just need to know where the button is located:
- Long into /wp-admin/
- Click on WP Engine button located at the left top side.
284w" sizes="(max-width: 284px) 100vw, 284px">
- Click “Purge all caches.”
Finally, clear your browser cache and refresh your page. Once you refresh the page you should notice that the content has updated. If it is still not updating, you may want to consider contacting support by creating a support ticket
To know more about WPEngine caching system, please check it out here: https://wpengine.com/support/cache/
Hope this helps.