[Resolved] Translated menu items disappear after saving – unable to build French menu

Problem:
The client was unable to save translated menu items in a French navigation menu on a bilingual WordPress site using WPML. The menu items disappeared after saving, and when attempting to create a French menu, it reverted to English. The issue was traced to an interaction with WordPress.com's internal object caching system, affecting nav_menu_item post types and multilingual content.
Solution:
The solution involved manually clearing the object cache on WordPress.com's servers, which resolved the issue, allowing both French and English menus to save correctly. Additionally, we recommended activating the "Adjust IDs for multilingual functionality" option in WPML --> Languages. If the problem persists, we suggested asking WordPress.com to comment out the following function in the file

/wp-content/plugins/sitepress-multilingual-cms/inc/taxonomy-term-translation/nav-menu-translation/wpml-nav-menu-actions.class.php

by using:

add_action( 'wp_update_nav_menu_item', array( $this, 'wp_update_nav_menu_item' ), 10, 3 );

If this solution does not resolve your issue, or if it seems outdated or irrelevant to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If further assistance is needed, please open a new support ticket at WPML support forum.