Attempt to deal with changing login account name issue

Question

Like many companies, we have on a regular basis people who change names due to life situations. I have tried a variety of things to deal with this in SharePoint.
The changes start with the Active Directory admins, who create the user's new login during a night shift. I get an email about the change. When I look in the user profiles, I see that many of the fields for the user reflect the change. However, the
actual account name attribute, which is read only to me, never changes during this period.
So this morning, I once again web searched, found
http://geekswithblogs.net/rgupta/archive/2011/02/16/change-accountnameloginname-for-a-sharepoint-user-spuser-again.aspx and tried the recommendation.
I ran
stsadm -o migrateuser -oldlogin mydomain\old -newlogin mydomain\new -ignoresidhistory
The user does not exist or is not unique.
PS C:\Users\sa_spfarm>
This is the type of behavior I have gotten over time.
For the longest time I didn't do anything since the user profile was mostly updated. Then an InfoPath programmer reported getting stale information when trying to get the user's login. After research we found that it was using the account name for the user
rather than the login attribute (which is properly updated).
Several times I went through adding all the people who had out of date info in their user profile.
I recently tried to write some powershell that would at least produce a report for me of all  users in the farm whose account name differed from their logins - I was never able to get code that actually worked.
Surely there is something simple that I am missing. I am hoping someone reads this who recognizes the problem and lets me know.
The user profile sync is running - new user profiles appear in the system each day and as I said, in all the cases I have seen, the AD information in the profile has all been updated - except the account name (which I suspect must be an index key or something
for the profiles).
Thanks!
About the only thing I have seen that works is to go into all dozen or more of our site collections and add the user's new login to an appropriate sharepoint permission group - that seems to force the account name update or at least removes the old entry
and creates a new one (I am uncertain which it does).

Answer 1

Hmm. Let me see if I can.
Okay, so if you look at the 3 entries from the detailed user list of one of our site collections, you will see that most users are like the first and last one in this screen shot - where the login column and the user name column have the "same"
name (one has a domain and the other doesn't... that isn't the issue to which I am referring).
The middle person however has a user name which was the last login the user had, and has a login string with the correct domain and the correct login.
When I go to Central Admin > manage service applications > User Profile Service Application > Manage User Profiles and I search for the old name, it is not found in either the missing or the active user profiles.
When I search for the new name, a user profile is found. When I read through the user profile, there is no attribute which has the value of the old name.
There are calls from users in this situation which lead us back to user list information like this.
I have seen a user who was able to sign a document out for change in a doc library, but who could not sign it back in because "it was already out to another person" where the other person is the old name.
Likewise, as I mentioned, if an InfoPath attempts to pull the user's information back from the sharepoint web service, there have been, at least for us, times when the old name is returned with certain methods instead of the new name.
The interesting thing in this case is that normally I can fix these by adding the new login into a sharepoint group for the site collection. So far, that has not helped with this user.