Hi There,
Thanks for writing in!
Can you please update the theme to most recent version and let us know if that fixes your issue?
This latest release contains fixes for several issues so be sure to check out the changelog (http://theme.co/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.-
If you already have updated and reverted back to X 6.1.6 and Cornerstone 3.1.6, you still need to clear your caching plugin first before your test your site again. And if you are using W3 Total Cache. What you may have encounter could be just a caching issue.
Please let us know how it goes.