Calendar API sometimes returns NULL Event Attendees - google-calendar-api

Question

Has anybody come across an issue with the V3 Calendar API where sometimes the Attendee data is returned empty even though there are valid attendees on an Event?
The Events always have valid attendees.
An Event Get returns Attendees = NULL
Here is a code snippet of an Event Query
calendarToolsV3 cv3 = new calendarToolsV3(true, calendar, int.Parse(organisationId));
EventsResource.GetRequest gr = new EventsResource.GetRequest(cv3.service, calendar, eventId);
gr.AlwaysIncludeEmail = true;
Event evv = gr.Execute();
litDiagnosis.Text = "Summary | " + evv.Summary + "<br/>";
litDiagnosis.Text += "Id | " + evv.Id + "<br/>";
litDiagnosis.Text += "RecurringEventId | " + evv.RecurringEventId + "<br/>";
litDiagnosis.Text += "Status | " + evv.Status + "<br/>";
litDiagnosis.Text += "Visibility | " + evv.Visibility + "<br/>";
litDiagnosis.Text += "Start | " + (evv.Start == null ? evv.Start.Date.ToString() : evv.Start.DateTime.ToString() + "<br/>");
if (evv.Attendees != null && evv.Attendees.Count() > 0)
{
foreach (EventAttendee ea in evv.Attendees)
{
litDiagnosis.Text += "Attendee | " + ea.Email + "|" + ea.ResponseStatus + "<br/>";
}
}
****** EDIT **************
I have done some further testing and it seems that this occurs where the original APPT is a recurring APPT.
The user that I am interrogating the Event with has declined the Event
The attendees are no longer visible to that user.
The attendees are however visible to the Creator of the Event. When the Event is deleted the Attendees become visible again to that user?
When the Event is not Recurring this behaviour is not observed and all users can view all Attendees even when declined/deleted?
*********************** EXAMPLE CAPTURE FROM API EXPLORER ***************
Event Created by admin#i3000.co. Attendee Lisa.Jones#i3000.co queries the Event and can see the Attendess
{
"kind": "calendar#event",
"etag": "\"2869345662384000\"",
"id": "7d3pmni42o6pg6taeudsskhfh8",
"status": "confirmed",
"htmlLink": "https://www.google.com/calendar/event?eid=N2QzcG1uaTQybzZwZzZ0YWV1ZHNza2hmaDhfMjAxNTA2MTlUMjIwMDAwWiBsaXNhLmpvbmVzQGkzMDAwLmNv",
"created": "2015-06-19T00:13:22.000Z",
"updated": "2015-06-19T00:13:51.192Z",
"summary": "ATTENDEE TEST",
"colorId": "11",
"creator": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"organizer": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"start": {
"dateTime": "2015-06-20T08:00:00+10:00",
"timeZone": "America/New_York"
},
"end": {
"dateTime": "2015-06-20T09:00:00+10:00",
"timeZone": "America/New_York"
},
"recurrence": [
"RRULE:FREQ=WEEKLY;COUNT=2;BYDAY=FR"
],
"iCalUID": "7d3pmni42o6pg6taeudsskhfh8#google.com",
"sequence": 0,
"attendees": [
{
"email": "admin#i3000.co",
"displayName": "Admin User",
"organizer": true,
"responseStatus": "accepted"
},
{
"email": "lisa.jones#i3000.co",
"displayName": "lisa jones",
"self": true,
"responseStatus": "needsAction"
}
],
"extendedProperties": {
"private": {
"ilink": "recur7d3pmni42o6pg6taeudsskhfh8"
}
},
"hangoutLink": "https://plus.google.com/hangouts/_/i3000.co/admin-lisa-jone?hceid=YWRtaW5AaTMwMDAuY28.7d3pmni42o6pg6taeudsskhfh8",
"reminders": {
"useDefault": true
}
}
Lisa.Jones Removes the Event from her Calendar and Queries again - Attendees are not Visible
{
"kind": "calendar#event",
"etag": "\"2869346050176000\"",
"id": "7d3pmni42o6pg6taeudsskhfh8",
"status": "cancelled",
"htmlLink": "https://www.google.com/calendar/event?eid=N2QzcG1uaTQybzZwZzZ0YWV1ZHNza2hmaDhfMjAxNTA2MTlUMjIwMDAwWiBsaXNhLmpvbmVzQGkzMDAwLmNv",
"created": "2015-06-19T00:13:22.000Z",
"updated": "2015-06-19T00:17:05.088Z",
"summary": "ATTENDEE TEST",
"colorId": "11",
"creator": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"organizer": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"start": {
"dateTime": "2015-06-20T08:00:00+10:00",
"timeZone": "America/New_York"
},
"end": {
"dateTime": "2015-06-20T09:00:00+10:00",
"timeZone": "America/New_York"
},
"recurrence": [
"RRULE:FREQ=WEEKLY;COUNT=2;BYDAY=FR"
],
"iCalUID": "7d3pmni42o6pg6taeudsskhfh8#google.com",
"sequence": 0,
"extendedProperties": {
"private": {
"ilink": "recur7d3pmni42o6pg6taeudsskhfh8"
}
},
"hangoutLink": "https://plus.google.com/hangouts/_/i3000.co/admin-lisa-jone?hceid=YWRtaW5AaTMwMDAuY28.7d3pmni42o6pg6taeudsskhfh8",
"reminders": {
"useDefault": true
}
}
Admin#i3000.co now deletes the Event. When Lisa.Jones Queries the Event the Attendees are again visible
{
"kind": "calendar#event",
"etag": "\"2869346122438000\"",
"id": "7d3pmni42o6pg6taeudsskhfh8",
"status": "cancelled",
"htmlLink": "https://www.google.com/calendar/event?eid=N2QzcG1uaTQybzZwZzZ0YWV1ZHNza2hmaDhfMjAxNTA2MTlUMjIwMDAwWiBsaXNhLmpvbmVzQGkzMDAwLmNv",
"created": "2015-06-19T00:13:22.000Z",
"updated": "2015-06-19T00:17:41.219Z",
"summary": "ATTENDEE TEST",
"colorId": "11",
"creator": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"organizer": {
"email": "admin#i3000.co",
"displayName": "Admin User"
},
"start": {
"dateTime": "2015-06-20T08:00:00+10:00",
"timeZone": "America/New_York"
},
"end": {
"dateTime": "2015-06-20T09:00:00+10:00",
"timeZone": "America/New_York"
},
"recurrence": [
"RRULE:FREQ=WEEKLY;COUNT=2;BYDAY=FR"
],
"iCalUID": "7d3pmni42o6pg6taeudsskhfh8#google.com",
"sequence": 1,
"attendees": [
{
"email": "lisa.jones#i3000.co",
"displayName": "lisa jones",
"self": true,
"responseStatus": "needsAction"
},
{
"email": "admin#i3000.co",
"displayName": "Admin User",
"organizer": true,
"responseStatus": "accepted"
}
],
"extendedProperties": {
"private": {
"ilink": "recur7d3pmni42o6pg6taeudsskhfh8"
}
},
"hangoutLink": "https://plus.google.com/hangouts/_/i3000.co/admin-lisa-jone?hceid=YWRtaW5AaTMwMDAuY28.7d3pmni42o6pg6taeudsskhfh8",
"reminders": {
"useDefault": true
}
}