Syncing problems come in two flavors: easily resolved sweet and oh, my aching head sour.Unfortunately, you've seemingly bitten into a lemon here.For more information see: Exchange Outlook Calendaring Problems.
I experienced this while I was traveling in late September 2012 -- the missing appointments were my itinerary which was in a calendar I share with my executive assistant.
If the appointment shows up on your i OS device when you change it to a non-shared calendar, then that entire shared calendar might not be syncing to i OS devices anymore.
Although Google updates the calendar automatically from the Timetastic feed the timescales for this are somewhat unclear and there is no manual way to force the update.
Some observers have suggested Google updates every few hours, but Google themselves quote it may take up to 12 hours, although in in exceptional cases we have seen it take as long as 48 hours.
I was planning to migrate my "Appointments" to "Appointments2" using Outlook (because its easy) ...
BUT its very comforting to realise that I'm not alone and someone else came up with this already!If you've noticed missing calendar appointments (e.g., lost meetings, delegate issues), or meeting updates from someone other than the original organizer, you're not alone.This issue has been reported in organizations with Microsoft Exchange, Outlook (2010, 2013 or 2016), Apple i Phones/i Pads, Active Sync devices, Apple Macs running Outlook 2011 or 2016, and RIM Blackberries.Calendar on the drop down; if the event type shows under "on my mac", select the same colour under the "i Cloud" portion Next refresh your phone calendar as per above, by swiping down on the (daily) notes section of the calendar app. I had this problem and turned out that a setting had been put in place to only sync calendars 1 month back (Go to Settings. I changed it to Sync All Events, turned phone off then on, and voila.i Cloud calendar, it is possible that syncing no longer works for that entire calendar.The new shared calendar should accept new appointments and sync them to all devices, but it won't have the appointments from your old broken shared calendar.