Hi @Marco,
I have thoroughly checked your site and found the issue you have mentioned, by activating the parent theme and reactivating the child has resolved the issue.
If you are still facing the same issue, there might be a few different reasons behind the issue you are having. I would suggest you troubleshot a few common issues to find the reason behind it.
1.Plugin Conflict
2.Child Theme Related issue ** if you have activated it.
3.CSS/JS Customization
4.Disabling Cache
If you discover that an issue is coming from a custom code or 3rd party plugin, kindly consult with a developer or contact the plugin author. Please note that we do not provide support for custom codes and 3rd party plugins.
If that does not help, please copy your live site to a staging server so we could troubleshoot freely without breaking your live site.
And give us access in the secure note including:
– WordPress Site URL & Login URL
– WordPress Admin username/password
To create a secure note, click the key icon underneath any of your posts.
Please note that a few hours ago we have released another version of the Cornerstone with some fixes, I would recommend you to update your plugin to the latest one.
Thanks