Modifying a custom field results with a new custom field

Overview of the issue

If you edit an existing custom field that contains a JSON value but it is also set to Copy in WPML → Settings, you will find that the custom field translation is not updated. Instead, a new entry is created in the post.

Workaround

The problem has already been identified by our developers and will be solved soon.
As a workaround:

1. Complete a full backup of your site, files and database.
2. Edit /sitepress-multilingual-cms/classes/custom-field-translation/class-wpml-sync-custom-fields.php line number 63.
3. Replace

   delete_post_meta( $post_id_to, $meta_key, maybe_unserialize( $v ) );
   

4. With:

   delete_post_meta( $post_id_to, $meta_key, wp_slash( maybe_unserialize( $v ) ) );