Yeah, this is getting confusing, let me clarify this first. This is your dev site
https://dev.axis.org/ right? This site has no issue its X and Cornerstone are up to date and its working (see this test page).
And this is your live site
https://virtual.axis.org/ now you have an issue with this site because its X (4.3.2) and Cornerstone (3.0.4) version is not compatible.
Normally we will advise you to update the X to the latest version (6.0.4) so they will become compatible with your Cornerstone (3.0.4). But you mentioned above that your schedule would not allow you to troubleshoot the minor issues that will occur if you update the X.
So what I advise for now is downgrade your Cornerstone to the version that is compatible with X (4.3.2). To do this, please navigate to Plugins panel and deactivate and delete the current Cornerstone (3.0.4).
Then navigate to X Addons panel and wait for a few seconds, then navigate back to Plugins panel, you'll see that a lower version of Cornerstone is re-install, X automatically did that for you and that is the version that is compatible with your X (4.3.2). With this your X and Cornerstone should work seamlessly now.
Remember to clear all caches (plugin, server-side, CDN, and browser's cache) after downgrading so that the right code from the right version is always in use. This will help you to avoid any potential errors.
If you attempt to update X and Cornerstone in the future and stumble to an issue. Don't hesitate to create a new thread.
Hope this shed some lights,