I am using Office.context.mailbox.item.saveAsync in an Outlook add-in to save a new appointment. The returned item id is used to fetch the appointment using the REST api (a get request to Office.context.mailbox.restUrl + '/v2.0/me/events/' + itemId). This returns an appointment where Start, End, and Organizer is set correctly, but the Subject, Body, Location, Recurrence, Attendees is not set.
Does saveAsync not save all fields on the appointment?
I am using the REST api because the Recurrence field is not available through the Office.context.mailbox.item in older versions of the Outlook JavaScript API.