NPE when adding routes to app-peer

This is affecting Nitrogen CSIT. Robot symptom is prefixes missing [0], but the reason is visible in configurer tool log [1] and in karaf.log [2] (at 05:45:12,953):

2017-08-14 05:45:12,953 | ERROR | qtp573170128-423 | ContainerResponse | 33 - com.sun.jersey.jersey-server - 1.17.0 | The RuntimeException could not be mapped to a response, re-throwing to the HTTP container
java.lang.NullPointerException
at org.opendaylight.controller.cluster.databroker.AbstractDOMBrokerWriteTransaction.checkInstanceIdentifierReferencesData(AbstractDOMBrokerWriteTransaction.java:87)
at org.opendaylight.controller.cluster.databroker.AbstractDOMBrokerWriteTransaction.put(AbstractDOMBrokerWriteTransaction.java:79)
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.simplePostPut(BrokerFacade.java:941)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.makeNormalPost(BrokerFacade.java:890)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.postData(BrokerFacade.java:707)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.postDataViaTransaction(BrokerFacade.java:689)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.BrokerFacade.commitConfigurationDataPost(BrokerFacade.java:468)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.RestconfImpl.createConfigurationData(RestconfImpl.java:973)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.RestconfImpl.createConfigurationData(RestconfImpl.java:920)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.restconf.impl.StatisticsRestconfServiceWrapper.createConfigurationData(StatisticsRestconfServiceWrapper.java:157)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]
at org.opendaylight.netconf.sal.rest.impl.RestconfCompositeWrapper.createConfigurationData(RestconfCompositeWrapper.java:92)[313:org.opendaylight.netconf.sal-rest-connector:1.6.0.SNAPSHOT]

It is possible that this is just a consequence of the preceding BGPCEP-683 symptoms.

[0] https://logs.opendaylight.org/releng/jenkins092/bgpcep-csit-1node-userfeatures-only-nitrogen/113/log.html.gz#s1-s5-t5-k2-k2-k1-k6
[1] https://logs.opendaylight.org/releng/jenkins092/bgpcep-csit-1node-userfeatures-only-nitrogen/113/bgp_app_peer_initial_post_tc1.log.gz
[2] https://logs.opendaylight.org/releng/jenkins092/bgpcep-csit-1node-userfeatures-only-nitrogen/113/odl1_karaf.log.gz