Hi Matthew,
I notice you replied to the thread http://community.office365.com/en-us/f/153/t/319095.aspx and have a similar issue. For further investigation, let’s focuses on one specific user and I would like to collect some more information:
1.The detailed version of Outlook for Mac. And does he use any other Outlook client or mobile devices?
2.Are all the recurring meetings are duplicated?
3.If you disabled all the clients including Outlook for Mac and mobile devices, and create a new recurring meeting in Outlook Web App, is it duplicated?
Moreover, if you are able to reproduce the issue, please provide the steps at your convenience. Thanks for your time and efforts.
Best Regards,
Alex