Long Logon Times For Users Not Connected to Domain Network

I am experiencing an issue similar to here: http://social.technet.microsoft.com/Forums/windows/en-US/577ab221-8fe1-4e29-9a3f-5ea9c0d7faa8/logon-takes-very-long-when-connected-to-foreign-network-using-domain-login?forum=w7itproperf

Environment is Windows Server 2012 DCs with Windows 8 clients.

For our clients using Win 8, logon times:

1. Connect to our domain network: 5-15 seconds
2. Connected to a non-domain network: ~60 seconds
3. Not connected to any network: ~60 seconds

Partial solution was to set GPO Computer Configuration\Policies\Administrative Templates\System\User Profiles\Set maximum wait time for the network is a user has a roaming user profile or remote home directory to 5 seconds.

This has had the following effect:

1. Connect to our domain network: 5-15 seconds
2. Connected to a non-domain network: ~60 seconds
3. Not connected to any network: 10-15 seconds

The effect of this GPO is that when not connected to any network, the login is now very quick. But, we are still having very long login times when connected to a non-domain network (such as when remote users are auto connected to their home wifi when their computer boots up).

Any suggestions?