Currently Being ModeratedJul 24, 2013 12:07 PM (in response to kiwifromky)
This issue seems to come up pretty often. I've found a lot of the time it can be related to the cache *.ost file being corrupted on the computer which is host of the users Outlook account. I would turn caching off, delete the file, turn caching back on and let it be rebuilt. The other thing I do( as long as OWA is correct) is turn off calendar delivery under account settings on the iOS device, reset the device with home and power button, then turn calendar sync back on. Neither of these are cure-it-alls by any means. I think the real issue is the EAS protocol. Maintaining consistent Mail delivery to multiple endpoints is an extremely complex problem. Some Ways to mitigate are to educate users on Calendaring best practices
and have them be careful deleting or modifying intermediate instances of recurring appointments. Also, have only 1 delegate.
There are a number of lengthy threads here about this issue that cover it in far more detail than I have shared here. I'm not convinced there is truly a "fix" for this out there. There is a lot of info on this issue and discussion in some older threads.