If you’ve noticed missing calendar appointments (e.g., lost meetings, delegate issues), or meeting updates from someone other than the original organizer, you’re not alone. This issue has been reported in organizations with Microsoft Exchange, Outlook (2003, 2007, or 2010), Apple iPhones/iPads/iPods, Active Sync devices, Apple Macs running Entourage or Outlook 2011, and RIM Blackberries.
For more information please see: http://its.uiowa.edu/support/article/3521