This is possibly just another symptom of BGPCEP-267.
When applying workaround described in BGPCEP-277 the following appears in karaf.log

2015-10-16 12:37:05,858 | WARN | lt-dispatcher-19 | SimpleShardDataTreeCohort | 139 - org.opendaylight.controller.sal-distributed-datastore - 1.3.0.SNAPSHOT | Store Tx member-1-txn-36: Conflicting modification for path /(urn:TBD:params:xml:ns:yang:network-topology?revision=2013-10-21)network-topology/topology/topology[

{(urn:TBD:params:xml:ns:yang:network-topology?revision=2013-10-21)topology-id=pcep-topology}

].
2015-10-16 12:37:05,861 | ERROR | lt-dispatcher-39 | LocalThreePhaseCommitCohort | 139 - org.opendaylight.controller.sal-distributed-datastore - 1.3.0.SNAPSHOT | Failed to prepare transaction member-1-txn-36 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 was deleted by other transaction.]]}

Many more exceptions follow, see https://jenkins.opendaylight.org/sandbox/job/bgpcep-csit-1node-userfeatures-only-beryllium/15/artifact/karaf.log
(the link will go invalid during this weekend).