OptimisticLockFailedException: removeOrUpdateVpnToDpnList: Error removing from dpnToVpnList

2017-11-16 21:57:38,932 | ERROR | lt-dispatcher-22 | LocalThreePhaseCommitCohort      | 217 - org.opendaylight.controller.sal-distributed-datastore - 1.7.0.SNAPSHOT | Failed to prepare transaction member-1-datastore-operational-fe-0-txn-17999-0 on backend
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 children was modified by other transaction]]}
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)[415:org.scala-lang.scala-library:2.11.11.v20170413-090219-8a413ba7cc]
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
2017-11-16 21:57:38,932 | WARN  | lt-dispatcher-21 | ConcurrentDOMDataBroker          | 217 - org.opendaylight.controller.sal-distributed-datastore - 1.7.0.SNAPSHOT | Tx: DOM-44433 Error during phase CAN_COMMIT, starting Abort
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 children was modified by other transaction]]}
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)[415:org.scala-lang.scala-library:2.11.11.v20170413-090219-8a413ba7cc]
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
2017-11-16 21:57:38,936 | ERROR | nPool-1-worker-1 | VpnFootprintService              | 346 - org.opendaylight.netvirt.vpnmanager-impl - 0.6.0.SNAPSHOT | removeOrUpdateVpnToDpnList: Error removing from dpnToVpnList for vpn 77eaa407-bb84-4fe4-9dae-93de63b099bb vpnId 100015 interface 8b52b434-51af-4564-a8aa-7db48b78dd70 dpn 88896614250877
java.util.concurrent.ExecutionException: 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 children was modified by other transaction]]}
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)[:1.8.0_151]
Caused by: 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 children was modified by other transaction]]}
Caused by: 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 children was modified by other transaction]]}
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)[415:org.scala-lang.scala-library:2.11.11.v20170413-090219-8a413ba7cc]
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
Caused by: org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node children was modified by other transaction
2017-11-16 21:57:38,940 | ERROR | nPool-1-worker-1 | JobCoordinatorImpl               | 261 - org.opendaylight.infrautils.jobcoordinator-impl - 1.3.0.SNAPSHOT | Exception when executing jobEntry: JobEntry{key='VPNINTERFACE-8b52b434-51af-4564-a8aa-7db48b78dd70', mainWorker=org.opendaylight.netvirt.vpnmanager.VpnInterfaceOpListener$$Lambda$813/2010848516@2d07da51, rollbackWorker=null, retryCount=0, futures=null}
java.lang.RuntimeException: 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 children was modified by other transaction]]}