Actually, this has been happening to me on Mac OS X as well since I moved to my current job, and I’m surprised it took the iOS update to make this a hot issue.
I had never had this issue before switching jobs, and I believe it to be an Exchange problem, similar to the “can’t update event on server” bug that happens when you don’t have timezones enabled - the server somehow mis-parses the updates sent by the client and gets seriously confused.
It also happens when you delete an event from your calendar - even if it isn’t yours, you’ll end up sending out cancellation updates, sometimes to hundreds of people at a time…
I sincerely hope they fix it on both platforms.