Background of the issue:
translate a custom post into another language. Under settings, I said that the event language should be copied. But the event language is not copied. Furthermore, I cannot edit the event language of a translated post. When I click on update, the change is not saved and the event language is not adapted.
First of all, I'll recommend updating WordPress to the latest version and then recheck for the problem.
IMPORTANT: Please take full backup of your website and database beforehand.
If problem is still there, then please try the following:
1) Take a full backup of your site and database before proceeding.
2) Deactivate all plugins except WPML, String Translation, Elementor and the plugin bringing up these custom fields.
3) Check for the issue if it still happens.
Please let me know your findings and I'll try my best to help you further on the matter.
I need to take a closer look at your site. So I request temporary access (WP-Admin and FTP), preferably to a test site where the problem has been replicated.
Your next answer will be private, to share this information safely.
Also provide detailed steps to reproduce the issue and links to pages in the admin and on the frontend.
IMPORTANT: Please take a complete backup of the site to avoid data loss. I may need to activate/deactivate plugins also.