Hey Carsten,
We currently don’t have any reports regarding MEC. May we have access to your WordPress Admin and the URL of the page with issue so we could check your setup and so we could replicate it in our test site to know if this is a bug? Please send the credentials in a Secure Note.
Also, please ensure everything is up to date according to our Version Compatibility list at https://theme.co/apex/forum/t/troubleshooting-version-compatibility/195
May we also know if you’ve tried testing for a plugin conflict? It is possible that a third-party plugin is causing the issue. In case you don’t know the procedure, you can do this by deactivating all third-party plugins, and seeing if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
Thanks.