So far I have only seen this in our environment when someone has a delegate who is also the delegate of other people. User 1, User 2, and User 3 all use User 4 as their delegate. Users 1-3 have iOS phones and User 4 does NOT. User 4 creates a meeting on behalf of User 1 and invites Users 2 and 3 (along with other attendees). User 4 accepts it on behalf of Users 2 and 3. User 2 sends a cancellation and becomes the owner of a new event of the same name/time/location that is only sent to himself. I know that it is not the original item as his Sent Items contains both a cancelation notification and a meeting invite sent only to himself
What is particularly odd about this is that he never processed the meeting/request from his iOS device (or so goes the claim).
As to everyone else making comments about iOS 5, yes, there has been issues with that and Calendars, but honestly, I don't recall a version of iOS that never had some problem with Calendars. It has been quirky for as long as I have been using it (which was iOS 3).
Lastly, what would it take to simply "Block" ActiveSync commands that don't properly cater to the specifications? My understanding is that iOS does something incorrectly that Exchange doesn't allow, but at the same time doesn't block. Like running a stop sign; I’m not “allowed” to run a stop sign, but I am never penalized for it unless a police officer catches me in the act. At what point can Exchange become a traffic cop, or would that create issues (political or otherwise) with the ActiveSync licensees?