My calendar is managed with a paid Google apps account. Hence, mail, contacts and calendar is synced using ActiveSync.
I recent weeks I discovered some issues in my Q10 calendar:
Ghost entries: the monthly view shows an appointment on a given day. When switching to the day view, no appointment is visible.
Duplicated entries: Some entries are duplicated on my Q10. As far as I can see, it's only there (no duplicated entries in the Mac Calendar app).
Missing entries: this is most annoying issue. Entries get sometimes lost.
Am I'm the only user with these problems?
Is there a workaround or a fix?
My Q10 runs with 10.1MR.
I use active sync for my google apps account as well, and it's flawless..
I'd suggest you try deleting the account and re-syncing it. Also, after deleting but before re-adding the account.. make sure there aren't any calendar entries still on the device.. if so you have something corrupted there and might need do to a security wipe.