Calendar Sync on Android using zMobile

I am having an issue where I cannot see my appointments on my stock Android Calendar but I can create them. It seems like new appointments that are created on the phone are deleted from the phone as soon as the item is uploaded to the zimbra server.

I just upgraded to the latest zMobile client yesterday (1.8.15)

I have tried a number of different roms between jellybean and kitkat with the same result.

Email and contact sync are working perfectly.

Would anyone have any ideas on this?