Menu editor removes links from submenu items when updating parent menu item

Having a menu item with a submenu item, changing the menu item will result in a removal of the link in the sub menu item.

Reproduction path:

• Create a menu item, save it.
• Create a submenu item below the menu item you created, give it a link and save it. See screenshot1.png
• Update the parent menu item, e.g. change the title.
• See that the value of the link (internal or external) of the submenu item is removed. See screenshot2.png
• Expected result: the submenu item is not modified by changing the parent menu item.