This issue did not occur until we upgraded to Exchange Server 2010.
So, this is what happens:
select ADD ACCOUNT in Outlook 2011
enter the correct user info then un-check "Auto Configure Server"
enter our OWA address "https://mail.ourcompany.com"
The next day, the user will check their server setting and see that it's been changed to server name.company.local
I have no idea why this happens but I'm guessing it's related to Exchange 2010 since this did not occur with Exchange 2007.
Has anyone seen this before?