Hi Jade,
Thank you for providing the login information. I checked the website and now I can confirm that the problem is the cache and using the traditional methods of purging them using the wp-rocket plugin does not work.
Here is how I tested the case:
I went to the admin section and checked X > Validation and indeed the latest version is installed:
There is a trick that I can check if the latest version is actually shown on the front end of the website. I checked the front end while I was logged in and enabled the Google Chrome Developer Toolbar and checked the HTML body tag classes.
The X theme and the Cornerstone plugin echo the version number there. Upon checking I found out that the latest version is loaded and everything worked correctly:
Then I did another test. I opened up the Incognito Window of the Chrome browser and loaded the website. So in this case, I was not logged in, and the front end did not show correctly. Then I used the same method, and surprize surprize the code that is loaded is old enough to be 100% sure it will not work!
Now that we know exactly the problem cause, it comes how to go about and fix it. Unfortunately, we are not the experts on the methods that you used to cache the website and it will be better that you contact WP Rocket and CloudFlare support. Also, contacting your hosting service provider also might help as they have better control over the server and maybe they can help.
You can share my insight with the support staff of the third-party services to help them understand the case.
Thank you.