After a recent patch upgrade of smartermail (I'm not sure which one) a couple of our Outlook users reported their contact list got shifted over by one.  In other words, an email to bob@domain.com actually went to brian@domain.com (the next person in their contact list).  The "file as" and display name says bob@domain.com but the email address says brian@domain.com.

As you can imagine, this has potentially disastrous implications.  We have notified all our users to watch out for it, but has anybody experienced this?  What would be the cause of it?