Or else as suggested on Github :
Settings > Languages > Advanced and choose RAW instead of the LSB
As long as there is no real solution the quickest way to update the menu is to update mysql directly in phpmyadmin.
All posts with a menu_order value are the menu labels.
With this method it is possible to update only 1 label at a time.
Same here… Thanks for the tip 😉
Hope there will be a better solution than re-editing all the menu every time !!!