The following message keeps coming in the plugin logs.
Because of this operational ds is not updated with latest info from the switch.

2016-03-18 11:39:06,279 | WARN | n-invoker-impl-0 | TransactionInvokerImpl | 228 - org.opendaylight.ovsdb.hwvtepsouthbound-impl - 1.2.2.SNAPSHOT | Exception invoking Transaction:
java.lang.IllegalStateException: Previous transaction member-1-chn-9-txn-1605-1458297541317 is not ready yet
at org.opendaylight.controller.cluster.datastore.TransactionChainProxy$Allocated.checkReady(TransactionChainProxy.java:85)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.TransactionChainProxy.allocateWriteTransaction(TransactionChainProxy.java:192)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.datastore.TransactionChainProxy.newReadWriteTransaction(TransactionChainProxy.java:173)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.databroker.DOMBrokerReadWriteTransaction.createTransaction(DOMBrokerReadWriteTransaction.java:49)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.databroker.DOMBrokerReadWriteTransaction.createTransaction(DOMBrokerReadWriteTransaction.java:22)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.databroker.AbstractDOMBrokerTransaction.getSubtransaction(AbstractDOMBrokerTransaction.java:57)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.cluster.databroker.DOMBrokerReadWriteTransaction.read(DOMBrokerReadWriteTransaction.java:37)[146:org.opendaylight.controller.sal-distributed-datastore:1.3.1.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.AbstractForwardedTransaction.doRead(AbstractForwardedTransaction.java:63)[121:org.opendaylight.controller.sal-binding-broker-impl:1.3.1.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.BindingDOMReadWriteTransactionAdapter.read(BindingDOMReadWriteTransactionAdapter.java:31)[121:org.opendaylight.controller.sal-binding-broker-impl:1.3.1.SNAPSHOT]
at org.opendaylight.ovsdb.hwvtepsouthbound.HwvtepSouthboundUtil.readNode(HwvtepSouthboundUtil.java:68)[228:org.opendaylight.ovsdb.hwvtepsouthbound-impl:1.2.2.SNAPSHOT]
at org.opendaylight.ovsdb.hwvtepsouthbound.transactions.md.HwvtepManagerUpdateCommand.updateManager(HwvtepManagerUpdateCommand.java:60)[228:org.opendaylight.ovsdb.hwvtepsouthbound-impl:1.2.2.SNAPSHOT]
at org.opendaylight.ovsdb.hwvtepsouthbound.transactions.md.HwvtepManagerUpdateCommand.execute(HwvtepManagerUpdateCommand.java:54)[228:org.opendaylight.ovsdb.hwvtepsouthbound-impl:1.2.2.SNAPSHOT]
at org.opendaylight.ovsdb.hwvtepsouthbound.transactions.md.HwvtepOperationalCommandAggregator.execute(HwvtepOperationalCommandAggregator.java:46)[228:org.opendaylight.ovsdb.hwvtepsouthbound-impl:1.2.2.SNAPSHOT]
at org.opendaylight.ovsdb.hwvtepsouthbound.transactions.md.TransactionInvokerImpl.run(TransactionInvokerImpl.java:88)[228:org.opendaylight.ovsdb.hwvtepsouthbound-impl:1.2.2.SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)[:1.7.0_85]
at java.util.concurrent.FutureTask.run(FutureTask.java:262)[:1.7.0_85]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)[:1.7.0_85]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)[:1.7.0_85]
at java.lang.Thread.run(Thread.java:745)[:1.7.0_85]