in 3node tunnels fail to create due to concurrency lock - cluster behavior is missing

running netvirt-vpnservice-csit-3node-openstack-mitaka-openstack-boron
one of the computes is lacking tunnels rules in table 21 for all vms defined.
In the log, there is an error:

2016-09-11 13:18:04,672 | WARN | pool-45-thread-9 | TransportZoneNotificationUtil | 314 - org.opendaylight.netvirt.neutronvpn-impl - 0.3.0.SNAPSHOT | failed to add tunnels on router added of routerDpnList RouterDpnList{getDpnVpninterfacesList=[DpnVpninterfacesList{getDpnId=198081082022276, augmentations={}}, DpnVpninterfacesList{getDpnId=250746723134214, augmentations={}}, DpnVpninterfacesList{getDpnId=17607834328568, augmentations={}}], getRouterId=4ee3bdd3-b005-4e4f-b313-8e4d35503a85, augmentations={}} due to OptimisticLockFailedException

{message=Optimistic lock failed., errorList=[RpcError [message=Optimistic lock failed., severity=ERROR, errorType=APPLICATION, tag=resource-denied, applicationTag=null, info=null, cause=org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node was replaced by other transaction.]]}

Seems like the error was caused by multiple odls handling the same transport zone in TransportZoneNotificationUtil.