As far as I can tell its a database issue. Editing "any" account settings at all forces a sync to the DB and fixes the issue. So you checking that box or me adding/removing initials...anything really will fix the issue. Just a matter of how long it takes them to fix the issue.
I didn't see the second page of the topic until after I posted, but i was glad to find out we could make any change in the User Management.
However, what I found the other day was that on at least 1 affected user, if I changed the login name to all lowercase. I could keep resetting the password and not have to change anything in the User Management again.
The only thing is after a password change, the first time logging in crashes CPS. Then they are fine. I never had to go back into User Management for that user.
That's pretty cool, next time I have a user who has that issue I will give it a whirl.