Ruenel suggested the issue with WP Rocket to another user which is using it and made it clear that he is not sure if you are using it since there is no way for us to check your website since you did not provide further details. It was just suggestion that you could look into in case you are actually using WP Rocket.
Since you mentioned that you aren’t, kindly make sure that you have X and Cornerstone updated to the latest version. We’ve seen some cases of either Cornerstone or X being updated, but not both which causes an incompatibility issue.
In case you have X and Cornerstone updated to the latest version but the issue persists, kindly post a new thread and please provide us with the admin access to your site in a Secure Note: