ios calendar calendars randomly enabled
I am using the calendar app with my company's google apps account. I've configured my account to share a number of my co-workers, per these instructions (https://support.google.com/calendar/answer/151674?hl=en&ref_topic=13950). Everything is configured correctly: I see the calendars in my iphone calendar app and can select or deselect them. Unfortunately, after a while, some calendars will become randomly selected, and I get my co-workers calendar notifications, etc. I'm using the same calendar account on my desktop, iPad and iPhone. I've verified that none of the devices have these randomly checked co-worker calendars selected.
Has anyone seen this behaviour before and know the fix?
Thanks!