Calendar events getting cancelled status & missing details

I've been observing some events created on Gcal will get status cancelled after sometime.

{
"kind": "calendar#event",
"etag": "\"<some numbers>\"",
"id": "<id>",
"status": "cancelled",
"htmlLink": "https://www.google.com/calendar/event?eid=<eid>",
"updated": "2025-03-25T14:24:39.191Z",
"start": {
"dateTime": "1999-12-31T19:00:00-05:00",
"timeZone": "UTC"
},
"end": {
"dateTime": "2000-01-01T19:00:00-05:00",
"timeZone": "UTC"
},
"transparency": "transparent",
"iCalUID": "<id>@google.com"
}

1. The original start and end times get wrongly set
2. The event losses a bunch of fields which were originally set (summary, description, attendees, etc)
3. Making updates via api returns 403 (forbbiden) instead of 404 (for an event that is claimed to have been deleted.

{'domain': 'global', 'reason': 'forbidden', 'message': 'Forbidden'}

​I want to understand what could possibly happen for an event to be in this state.

​

This seems to happen when a user goes in to "Change Owner" after creating the event and you try retrieving the event via the old owner's calendar. Example, if the event was originally created on calendar_abc and is later goes through change of ownership to calendar_xyz, any operation on the event via the old calendar https://www.googleapis.com/calendar/v3/calendars/calendar_abc@group.calendar.google.com/events/{event_id}/ will throw a 403 instead of 404.

This explains why the event info under the old calendar returns somewhat scrubbed info.