Servers MUST ensure that "Attendees" only get information about recurrence instances that explicitly include them as an "Attendee", when delivering scheduling messages for recurring calendar components.
For example, if an "Attendee" is invited to only a single instance of a recurring event, the organizer scheduling object resource will contain an overridden instance in the form of a separate calendar component. That separate calendar component will include the "ATTENDEE" property referencing the "one-off" "Attendee". That "Attendee" will not be listed in any other calendar components in the scheduling object resource. Any scheduling messages delivered to the "Attendee" will only contain information about this overridden instance.
As another example, an "Attendee" could be excluded from one instance of a recurring event. In that case, the organizer scheduling object resource will include an overridden instance with an "ATTENDEE" list that does not include the "Attendee" being excluded. Any scheduling messages delivered to the "Attendee" will not specify the overridden instance but rather will include an "EXDATE" property in the "master" component that defines the recurrence set.