For the first time since starting to use the native calendar in iOS 7 on my iPhone 5, I attempted to delete a single occurrence of a weekly repeating event, and failed. I am syncing via Google (as an Exchange account). I can go through the motions of deleting the item, the option is there. But seconds after deleting the single occurrence, it popped back. I tried several times. At the time, the native calendar was the only calendar app installed, and the Google calendar was the only calendar configured within the application.
I re-installed CalenGoo, deleted the single occurrence through there, success first time.