User A creates a recurring event.
Moves one occurency to another time and/or date.
"Save and Close" her change.
Invites to the whole recurring event ("All occurencies") user B as attendee.
"Save and Close" her change.

Now A opens the changed occurency.
There is no indication that someone is invited to this event.

User B sees the recurring event in her calendar.
But the changed occurency is not part of the recurring event.
It seems to be a single event, which additionally seems accepted by B.
B didn't accept it!
The other occurencies are visible for B as recurring event awaiting acceptance.

When B opens the changed occurency, she can edit all attributes of this event.
That looks as if A had written this "single event" directly into Bs calendar.
But A does only have "View Date and Time" privileges granted to Bs calendar.