Duplicate SSN error not working as expected

Summary:

When adding a new person via Hire an Employee, Add Nonworker, and Add Contingent Worker, an error will appear right away when entering a national identifier that is already in the system. We recently discovered that if the duplicate national identifier is associated with a person that is restricted from the user, the error will not occur until the action has gone through approvals.

That is, John Doe is an HR Specialist limited to only see employees at Michigan. Mary Sue is an employee at Ohio with as national identifier of 12345. If John Doe adds a new nonworker with a national identifier if 12345. They are able to submit the action. The action will error and show failed in Transaction Console.