Calling the Prohibit modification method SetLockStateForDisplay has no effect

V9.2.1

Calling the Prohibit modification method SetLockStateForDisplay has no effect.

    Dim f As ISqlFormatter = Session.SqlFormatter
    Dim uidPerson = "368ec518-575c-4644-b0e2-d3f02110eb4c"
    
    If Session.Source.Exists("Person", f.UidComparison("UID_Person", uidPerson)) Then
        Dim person = Session.Source.Get("Person", uidPerson, EntityLoadType.Interactive)
		Dim columns As String() = New String() {"FirstName", "LastName"}
        person.CallMethod("SetLockStateForDisplay", columns, True)
    	person.Save(Session)
    End If

Also found the same unanswered question on the forum
https://www.oneidentity.com/community/identity-manager/f/forum/31431/prohibit-modification-for-some-selected-users/79070

Thank you,
Niels