I think you can remove the offending host by using qbadmin and referring to it by the MAC address:
qbadmin worker --remove 00:30:48:5A:71:5D
If that doesn't worker, you'll need to remove it by name or IP:
qbadmin worker --remove LAX-RF-029
If you're lucky, you'll get the down host removed. If both get removed, just use --clearbanned and restart the Worker:
qbadmin worker --clearbanned