When a rejoin event happens (an instance fails and restarts before GF knows it has failed), the status for it in 'asadmin get-health' shows started instead of rejoined. This is happening because the rejoin subevent is null in the JoinedAndReadyNotificationSignal. Am filing this for GF integration and will file a more technical one against Shoal to get the fix in.
This is a minor issue now because instances probably won't restart this quickly. But it would be good to get the fix in. To cause this, here's a snippet of domain.xml that leads to an absurdly long time to kill/restart an instance: