Menu user access control broken in V2.1.6

In 2.1.6 a bug was introduced that was not in 2.1.5. The symptom is that an attempt to change the user access of a menu item is ignored.
I have confirmed that the problem is in /includes/admin/core/class-admin-navmenu.php.
Copying that file from 2.1.5 resolves the problem.
This was tested in a sandbox, with no other plugins active and the 2020 theme (it is not theme-sensitive).
How to reproduce:
Go to Appearances, Menu
Open a menu item
Go to “Who can see this menu link?
Change the entry
Save the menu
Open the menu item again and observe it to did not change to the new setting.