Optimistic lock failed when configuring multiple devices serially during bootup

This Beryllium issue only happens in all job [0] and in the first of two very similar suites, so this is possibly an iteration with ODL still performing installation of some features. At the end of January there were two 100% pass test runs, but since then suite always fails during configuring additional devices (towards netconf testtool).

Even with patch for better synchronization [1], suite still fails after ~20 devices [2] on Sandbox. Looking at karaf.log there, several projects are listening on changes in topology-netconf (SFC, USC, Of-config, maybe more), but the error happened just after dsbenchamrk config files were applied:

2016-02-09 12:47:16,125 | INFO | config-pusher | DsbenchmarkProvider | 334 - org.opendaylight.controller.dsbenchmark - 1.1.0.SNAPSHOT | DataStore test oper status populated: TestStatus [_execStatus=Idle, _testsCompleted=0, augmentation=[]]
2016-02-09 12:47:16,125 | INFO | config-pusher | DsbenchmarkProvider | 334 - org.opendaylight.controller.dsbenchmark - 1.1.0.SNAPSHOT | DsbenchmarkProvider Session Initiated
2016-02-09 12:47:16,205 | INFO | config-pusher | ConfigPusherImpl | 96 - org.opendaylight.controller.config-persister-impl - 0.4.0.SNAPSHOT | Successfully pushed configuration snapshot dsbenchmark-impl-default-config.xml(odl-integration-compatible-with-all,odl-integration-compatible-with-all)
2016-02-09 12:47:16,205 | INFO | config-pusher | ConfigPusherImpl | 96 - org.opendaylight.controller.config-persister-impl - 0.4.0.SNAPSHOT | Pushing configuration snapshot ntfbenchmark-impl-default-config.xml(odl-integration-compatible-with-all,odl-integration-compatible-with-all)
2016-02-09 12:47:16,348 | ERROR | entLoopGroup-2-2 | TransactionProvider | 94 - org.opendaylight.controller.config-manager-facade-xml - 0.4.0.SNAPSHOT | Exception while commit of org.opendaylight.controller:TransactionName=ConfigTransaction-366-370,type=ConfigTransaction, aborting transaction
org.opendaylight.controller.config.api.ConflictingVersionException: Optimistic lock failed. Expected parent version 369, was 366

[0] https://jenkins.opendaylight.org/releng/view/netconf/job/netconf-csit-1node-periodic-scale-all-beryllium/
[1] https://git.opendaylight.org/gerrit/31692
[2] https://jenkins.opendaylight.org/sandbox/job/netconf-csit-1node-periodic-scale-all-beryllium/2/robot/report/log.html#s1-s2-t2-k2-k4-k17-k3-k1-k2-k2-k3-k6