There’s a couple issues with calendar events right now:
One, the event won’t display on the calendar for everyone who is invited. I have a calendar that has a few of my characters on it, and one of them is unable to see the entry entirely. It doesn’t even show on the date at all. Disabling addons does not do anything, but they all have the same UI anyway.
Edited to add: I am unable to see my own calendar entry currently. The event exists and I am on it, the corner of my minimap flashes, but when I open up the calendar, the event is not visible on the appropriate day, on this character. (I can see it, on my alt who is also on the calendar)
Two, trying to open the calendar entry on characters that do see it often generates the error “Can’t Find Event Creator.” This happens even to me when I am logged into the character that actually created the entry.