Hello,
In this post you can find usefull information regarding iOS 6.0 and Exchange issues articles :
iOS6 devices erroneously take ownership of meetings - Exchange Team Blog - Site Home - TechNet Blogs
http://blogs.technet.com/b/exchange/archive/2012/10/23/ios6-devices-erroneously-take-ownership-of-meetings.aspx
This one contains the most extense list of "issues" and how you will be able to address them :
Current issues with Microsoft Exchange ActiveSync and third-party devices
http://support.microsoft.com/kb/2563324
Here is one of the last we found :
Meeting in Attendee’s Calendar Loses Track of the Meeting Organizer
http://support.microsoft.com/kb/2768774
I hope this helps out :)
Kind regards,
João Ribeiro