Dead letters encountered in a basic 1node BGP test

This Beryllium bug may have a cause common with other bugs, but the symptom is different.

When using data with rib-instance (as specified in BGPCEP-244) in basic BGP suite (running after tcpmd5 suite but before other bgp suites), ODL disconnects the newly configured peer. Sandbox link [0].
The subsequent test cases within the suite (when ODL initiates and peer listens) pass. This may be a heisenbug.

[0] https://jenkins.opendaylight.org/sandbox/job/bgpcep-csit-1node-userfeatures-only-beryllium/8/robot/bgpcep-userfeatures.txt/Cases/

Part of karaf.log:

2016-02-01 14:35:10,370 | INFO | h for user karaf | command | 222 - org.apache.karaf.log.command - 3.0.3 | ROBOT MESSAGE: Starting test Start_Talking_BGP_speaker
2016-02-01 14:35:10,517 | INFO | oupCloseable-6-4 | StrictBGPPeerRegistry | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | BGP Open message session parameters differ, session still accepted.
2016-02-01 14:35:10,521 | INFO | oupCloseable-6-4 | BGPSessionImpl | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | BGP HoldTimer new value: 180
2016-02-01 14:35:10,528 | INFO | oupCloseable-6-4 | BGPPeer | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | Session with peer 10.30.32.191 went up with tables: [BgpTableTypeImpl [getAfi()=class org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.Ipv4AddressFamily, getSafi()=class org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.UnicastSubsequentAddressFamily]]
2016-02-01 14:35:10,540 | INFO | oupCloseable-6-4 | AbstractBGPSessionNegotiator | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | BGP Session with peer [id: 0xe5fb9375, /10.30.32.191:17900 => /10.30.32.188:1790] established successfully.
2016-02-01 14:35:10,737 | INFO | oupCloseable-6-4 | BGPSynchronization | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | BGP Synchronization finished for table TablesKey [_afi=class org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.Ipv4AddressFamily, _safi=class org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.UnicastSubsequentAddressFamily]
2016-02-01 14:35:11,098 | INFO | ult-dispatcher-3 | rovider$RemoteDeadLetterActorRef | 129 - com.typesafe.akka.slf4j - 2.3.14 | Message [org.opendaylight.controller.cluster.datastore.messages.CloseDataTreeChangeListenerRegistrationReply] from Actorakka://opendaylight-cluster-data/user/shardmanager-operational/member-1-shard-default-operational/$k#-221548343 to Actor[akka://opendaylight-cluster-data/deadLetters] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
2016-02-01 14:35:11,100 | INFO | entLoopGroup-2-2 | BGPSessionImpl | 305 - org.opendaylight.bgpcep.bgp-rib-impl - 0.5.0.SNAPSHOT | Closing session: BGPSessionImpl

{channel=[id: 0xe5fb9375, /10.30.32.191:17900 => /10.30.32.188:1790], state=UP}