Was on 2.2.1 (new install when we tested) - using same module version when I posted.
Since then, upgraded to 2.3.0 along with the module and changed to Azure AD Auth - thereby skipping this problem. However, the cmdlet still getting same object type from newer module.
(New-PSUAuthenticationResult -Success).GetType().FullName
Security.AuthenticationResult
Won’t be trying this in Universal since using Azure AD Auth now.