Hi @nadigitaladm1n,
We do not have previous version of the Cornerstone plugin and you need to contact your hosting service provider to provide you with a backup of your website containing the old version of the website.
Having said that, we will be happy to check and see what is the problem cause. We do not support conflict with third party plugins and it is outside of our support scope but we can take a look into the issue anyways to give you an idea where to start.
I suggest that you make sure that you have the compatible version of the Cornerstone and the X theme. Please go to Plugins menu deactivate Cornerstone plugin. And delete it. Then go to X > Validation menu and wait for few seconds and then get back to Plugins menu and activate the automatically installed Cornerstone plugin again.
Finally, I should mention that Cornerstone is a Page Builder and it does not have anything to do with the auto generated pages of third party plugins. That is why I am not sure that your assumption that the Cornerstone plugin is the problem cause is correct in the first place.
kindly get back to us with the result of the steps above and URL/User/Pass of your WordPress dashboard using the Secure Note functionality of the post to follow up the case if you still have problems.
Thank you.