GroupActivity.sessions() not receiving updated GroupSessions

While observing GroupSession objects for my GroupActivity via the .sessions() async sequence, updated sessions are never received with with new states. Neither state == .joined or state == invalidated are received after calling session.join() and session.leave() respectively:

Task {
    for await session in MyGroupActivity.sessions() {
        switch session.state {
        case .waiting:
            // Received after activating activity.
        case .joined:
            // Never received after calling `session.join()`.
        case .invalidated:
            // Never received after calling `session.leave()`, ending the FaceTime call, or after other participating user ends session for everyone.
        }
    }
}