Karaf log shows exception when clearing router GW

Steps:

1) Stack fresh openstack and ODL
2) Create external network/subnet:

neutron net-create ext-net --router:external --provider:physical_network public --provider:network_type flat

neutron subnet-create --name ext-subnet --allocation-pool start=192.168.56.9,end=192.168.56.14 --disable-dhcp --gateway 192.168.56.1 ext-net 192.168.56.0/24

3) Add router and set Gateway
neutron router-create ext-rtr
neutron router-gateway-set ext-rtr ext-net

4) clear Router GW

neutron router-gateway-clear ext-rtr

5) Exception shows in karaf log:

2017-08-09 17:25:13,964 | ERROR | eChangeHandler-0 | NatUtil | 369 - org.opendaylight.netvirt.natservice-impl - 0.4.2.SNAPSHOT | getVpnForRouter : VPN not found for routerID:22834ad3-0790-42e9-8703-ed78a5d47ce5
2017-08-09 17:25:13,964 | ERROR | eChangeHandler-0 | NatUtil | 369 - org.opendaylight.netvirt.natservice-impl - 0.4.2.SNAPSHOT | getVpnForRouter : VPN not found for routerID:22834ad3-0790-42e9-8703-ed78a5d47ce5
2017-08-09 17:25:13,964 | ERROR | eChangeHandler-0 | ExternalRoutersListener | 369 - org.opendaylight.netvirt.natservice-impl - 0.4.2.SNAPSHOT | addOrDelDefaultFibRouteForSNAT : No switches found for router 22834ad3-0790-42e9-8703-ed78a5d47ce5
2017-08-09 17:25:13,965 | ERROR | eChangeHandler-0 | VpnManagerImpl | 360 - org.opendaylight.netvirt.vpnmanager-impl - 0.4.2.SNAPSHOT | Failed to handle router GW flow in GW-MAC table. DPN id is missing for router-id 22834ad3-0790-42e9-8703-ed78a5d47ce5
2017-08-09 17:25:13,967 | WARN | eChangeHandler-0 | VpnManagerImpl | 360 - org.opendaylight.netvirt.vpnmanager-impl - 0.4.2.SNAPSHOT | Failed to install arp responder flows for router 22834ad3-0790-42e9-8703-ed78a5d47ce5. DPN id is missing.
2017-08-09 17:25:13,975 | INFO | eChangeHandler-0 | ExternalRoutersListener | 369 - org.opendaylight.netvirt.natservice-impl - 0.4.2.SNAPSHOT | handleDisableSnat : Entry
2017-08-09 17:25:13,977 | WARN | rd-dispatcher-48 | ShardDataTree | 211 - org.opendaylight.controller.sal-distributed-datastore - 1.5.2.SNAPSHOT | member-1-shard-default-config: Store Tx member-1-datastore-config-fe-0-txn-566-0: Data validation failed for path /(urn:opendaylight:netvirt:natservice?revision=2016-01-11)napt-switches/router-to-napt-switch.
org.opendaylight.yangtools.yang.data.api.schema.tree.ModifiedNodeDoesNotExistException: Node /(urn:opendaylight:netvirt:natservice?revision=2016-01-11)napt-switches/router-to-napt-switch does not exist. Cannot apply modification to its children.
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractNodeContainerModificationStrategy.checkTouchApplicable(AbstractNodeContainerModificationStrategy.java:281)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.SchemaAwareApplyOperation.checkApplicable(SchemaAwareApplyOperation.java:125)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractNodeContainerModificationStrategy.checkChildPreconditions(AbstractNodeContainerModificationStrategy.java:305)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractNodeContainerModificationStrategy.checkTouchApplicable(AbstractNodeContainerModificationStrategy.java:288)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.SchemaAwareApplyOperation.checkApplicable(SchemaAwareApplyOperation.java:125)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.StructuralContainerModificationStrategy.checkApplicable(StructuralContainerModificationStrategy.java:97)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractNodeContainerModificationStrategy.checkChildPreconditions(AbstractNodeContainerModificationStrategy.java:305)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractNodeContainerModificationStrategy.checkTouchApplicable(AbstractNodeContainerModificationStrategy.java:288)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.SchemaAwareApplyOperation.checkApplicable(SchemaAwareApplyOperation.java:125)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.RootModificationApplyOperation.checkApplicable(RootModificationApplyOperation.java:72)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.yangtools.yang.data.impl.schema.tree.AbstractDataTreeTip.validate(AbstractDataTreeTip.java:35)[108:org.opendaylight.yangtools.yang-data-impl:1.1.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardDataTree.lambda$processNextPendingTransaction$0(ShardDataTree.java:743)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardDataTree.processNextPending(ShardDataTree.java:789)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardDataTree.processNextPendingTransaction(ShardDataTree.java:736)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardDataTree.startCanCommit(ShardDataTree.java:819)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.SimpleShardDataTreeCohort.canCommit(SimpleShardDataTreeCohort.java:90)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.CohortEntry.canCommit(CohortEntry.java:97)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardCommitCoordinator.handleCanCommit(ShardCommitCoordinator.java:236)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.ShardCommitCoordinator.handleReadyLocalTransaction(ShardCommitCoordinator.java:200)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.Shard.handleReadyLocalTransaction(Shard.java:675)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.Shard.handleNonRaftCommand(Shard.java:316)[211:org.opendaylight.controller.sal-distributed-datastore:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.raft.RaftActor.handleCommand(RaftActor.java:270)[205:org.opendaylight.controller.sal-akka-raft:1.5.2.SNAPSHOT]
at org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor.onReceiveCommand(AbstractUntypedPersistentActor.java:31)[204:org.opendaylight.controller.sal-clustering-commons:1.5.2.SNAPSHOT]
at akka.persistence.UntypedPersistentActor.onReceive(PersistentActor.scala:170)[192:com.typesafe.akka.persistence:2.4.18]