continuous WARN logs when using neutron ports

2 parts: first, the '%s' seems like en error in the log
second, the warning never stops, repeating every 3 seconds

2015-02-25 18:36:38,026 | WARN | ds-oper-thread-0 | StatListenCommitFlow | 144 - slf4j.api - 1.7.2 | flow hashing hit a duplicate for FlowHashIdMapKey [_hash=Match [_ethernetMatch=EthernetMatch [_ethernetDestination=EthernetDestination [_address=MacAddress [_value=01:00:00:00:00:00], _mask=MacAddress [_value=01:00:00:00:00:00], augmentation=[]], augmentation=[]], _tunnel=Tunnel [_tunnelId=1001, augmentation=[]], augmentation=[GeneralAugMatchNotifUpdateFlowStats [_extensionList=[ExtensionList [_extension=Extension [augmentation=[NxAugMatchNotifUpdateFlowStats [_nxmNxReg=NxmNxReg [_reg=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg0, _value=2, augmentation=[]]]]], _extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg0Key, _key=ExtensionListKey [_extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg0Key], augmentation=[]]]]]]163840] -> Uri [_value=TunnelFloodOut_1001]. Exception %s was raised.