Using the .NET SDK to query Graph api for events. In cases where there are multiple attendees, the result data only includes the organizer and a maximum of 2 additional attendees in the Attendees collection.
var request = this.graphClient.Users[spaceId].Calendar.Events.Request();
Interestingly, when using the Graph Explorer I see the same behavior, though I cannot confirm that those meetings have more than 3 attendees. (https://developer.microsoft.com/en-us/graph/graph-explorer?request=me/calendar/events&method=GET&version=v1.0#)
Is this a default limit in the API itself, or perhaps an Exchange configuration that needs to be changed?