That is by design. Eventviewer only translate the GUID into an object. Try to run Get-EventLog -LogName Security -Newest 500 | ? { $_.EventID -eq 4662} |Format-List and you see that ObjectName is a GUID. You can get the object by Get-ADObject xxxxxxxx-1111-2222-3333-yyyyyyyyyyyyy. This is what the EventViewer is doing.