Recently support worked on an issue concerning how a logged on user's name is displayed in the FIM Portal. The information in this wiki goes through the steps to reproduce the issue, and possible work arounds to resolve the issue. The wiki assumes that you are familiar with working inside of the Microsoft Forefront Identity Manager product.
The SharePoint servers are not installed in a SharePoint Farm Configuration, so each server has its own SharePoint Database.
The display name of the user logged into the FIM Portal would not change, even if the user name in the Active Directory and the FIMService backend SQL Server database changed.
When a user first logs into a SharePoint Server, SharePoint looks in the user cache in the SharePoint database. If it does not find the user who is accessing the site, it adds that user to the database using the current naming values found in the Active Directory. If it does find the user ( by objectGuid or objectSID, not sure which), it does not go to the Active Directory to grab the naming attributes.