Impossible to delete menu item for removed Support client

I am not sure if this issue is related to another ticket, which I created minutes ago 🐛 Menu item for new client appears under the root of navigation menu, not under Support tickets Closed: outdated , but for some reason I can't delete menu items for the deleted Support clients. First of all the respective menu item was supposed to be automatically deleted when the client to which it belongs is deleted. But then it can't be deleted even separately, because there is no delete button in the menu system for the menu item at all. I even could not delete menu item for already deleted Support client going as Drupal user #1 to URL: https://mydomain.tld/admin/build/menu/item/701/delete This is strange, since user 1 have to have all the permissions of superadmin.