This is a human-readable label for the current stage of the multi-stage FSM sequence this vNet endpoint's sync is executing. Because a full sync involves several ordered stages, this description tells an admin which stage of that sequence this particular endpoint's process is currently in, which is more precise than the general FSM description field when a sync spans many discrete steps. A stage description of Local:VerifyMembership would tell the admin this endpoint's sync is currently verifying VLAN membership locally, before it would move on to a remote-verification stage.