For those of you who have AppleCare - PLEASE call the support line to report the issue. Apple's upper tier support addresses issues based on aggregated reports. These forums are not patrolled by Apple for these purposes. If they don't have enough reports of the issue in their internal database, the problem will not be addressed in a timely fashion. It's important that your "me too!" report go directly to Apple and not just sit here in the forums where we, the consumers, simply commiserate with each other.
If you have AppleCare, you can speak to someone by phone. Go to ExpressLane for iCloud: https://expresslane.apple.com/GetproductgroupList.do?PRKEYS=133314 and schedule a callback (it can be within 5 minutes, or you can schedule for a later time). You'll need the serial number for the product that your applecare covers (even tho this isn't isn't hardware-specific) and you'll select iCloud calendar issues as the topic. When you get a rep on the phone, explain the problem. You can tell them that there is another open ticket that you know of that reported the same problem. You can use my ticket number: 298865196.
They have to ask you to do some troubleshooting steps. It's their job. Go through the motions or tell them that you've already tried all the things they've suggested and that you are confident it's an iCloud server issue and not a device or hardware issue. Ask them for YOUR ticket/case # and write it down! Then, PLEASE ask to be escalated to a Senior Advisor and tell the Sr Advisor that you want your ticket to be added to the growing list of reports of this issue.
Again - the more people who report the problem accurately and thoroughly through AppleCare, the faster it will get escalted through engineering and resolved.
Message was edited by: justlaur fixed a typo