Hello,
The value is not saved due to a huge menu that has a lot of menu items. Due to the fact that the menu is very large – it created a form in the WordPress menu editor that has 11642 inputs – https://take.ms/HOa5n which, in turn, cannot be processed by your server due to its own settings.
In this situation, there are two solutions:
1. Increase PHP max_input_vars even more, to about 15000, to match the created menu.
2. Rebuilt the menu itself using the mega menu dropdowns created using the page builder (documentation https://xtemos.com/docs-topic/create-mega-menu/)
Kind Regards