There was problem that the 'offline' member os the GossipDeviceStore class was mismatched between distributed controllers. (refer to
The following CLI is provided to easily analyze these problems.
onos:device-local-available Lists all available devices in local device store
onos:device-local-offline Lists all offline info in local device store
onos:device-local-removal-request Lists all removal request info in local device store
CLI execution screen