We have a user who sent a single email to three recipients and each recipient received well over 500 copies of the email. The user/sender is running Outlook and ZCO version 5.0.3066.18 and we're running ZCS Network 5.0.19. We just upgraded to 5.0.19 from 5.0.16 on 09/29/2009.

Anybody else seeing similar behavior or know where I might look for the answer as to why this happened?