To see if I could reproduce the error by moving the account from the default Users folder back to the OU where it was I discovered that when I moved it to the Users folder the error went away. I put the user back in the OU where it came from and the error won't come back. I agree - weird indeed.
In summary, I guess if I move those users to the Users folder and back where they came from, the problem should be resolved. I'll have to test on a couple other users.