I came across such a situation wherein a change in Last/First Name (in Welcome Name or User Information) is not reflected when a user logs in. To address the issue, I ran the following SQL query on Shared Services Database and got few entries listed, this lets us understand that, for some reason, due to True value being set for the 'Moving' the User information is not getting reflected.
To address/resolve the issue, change the value of 'Moving' in the SiteSynch table to False by running the following command:
stsadm -o preparetomove -contentdb <server name: database name> -site <URL name> -undo
A change in the AD account name (ex: Last Name, First Name & Login Name) reflects in SharePoint "User Profiles and Properties" as and when there is an update through the Profile synchronization - incremental/full import. However, you may not see the changes of a user name whenever you login a SharePoint Site. This is because of lack of synchronization of User Information to the User Info table of a site content DB.
One of the reasons for such a scenario is described here. You may be aware of a posting on msdn regarding PrepareToMove command. A snippet of Todd's blog is:
If prepareToMove is run within a SharePoint farm that has at least the IU that Content DB will no longer participlate in profile syncronization; even if you remove and reattach the content DB to the same farm.
For more details, please refer to Todd's Blog -
select * from DBO.SiteSynch where Moving=1
You need to derive the details/values of the content DB name and URL from the listed details of the earlier command.
Then, run the following commands to synchronize the User Information.
1. stsadm -o sync -ignoreisactive 1
2. stsadm -o sync -deleteolddatabases 0
3. stsadm -o sync