Exception in SystemReadyService followed by system instability

The following exception has been observed in a number of CSIT and seems to be the first sign of general system level problems. For example, in this [0] CSIT run the openflow port is never opened.

{{2018-07-01T12:46:34,544 | ERROR | SystemReadyService-0 | SystemReadyImpl | 278 - org.opendaylight.infrautils.ready-impl - 1.4.0 | Failed unexpectedly (SystemReadyListeners are not called) }}
java.lang.NullPointerException: null
{{ at com.google.common.collect.Maps.doDifference(Maps.java:559) ~[?:?]}}
{{ at com.google.common.collect.Maps.difference(Maps.java:547) ~[?:?]}}
{{ at com.google.common.collect.Maps.difference(Maps.java:520) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter$Registration.addRpc(DOMRpcRouter.java:202) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter.notifyAdded(DOMRpcRouter.java:112) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter.lambda$registerRpcImplementation$0(DOMRpcRouter.java:81) ~[?:?]}}
{{ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?] }}
{{ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?] }}
{{ at java.lang.Thread.run(Thread.java:748) [?:?] }}
2018-07-01T12:46:34,675 | ERROR | SystemReadyService-0 | SystemReadyImpl | 278 - org.opendaylight.infrautils.ready-impl - 1.4.0 | Thread terminated due to uncaught exception: SystemReadyService-0
java.lang.NullPointerException: null
{{ at com.google.common.collect.Maps.doDifference(Maps.java:559) ~[?:?]}}
{{ at com.google.common.collect.Maps.difference(Maps.java:547) ~[?:?]}}
{{ at com.google.common.collect.Maps.difference(Maps.java:520) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter$Registration.addRpc(DOMRpcRouter.java:202) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter.notifyAdded(DOMRpcRouter.java:112) ~[?:?]}}
{{ at org.opendaylight.mdsal.dom.broker.DOMRpcRouter.lambda$registerRpcImplementation$0(DOMRpcRouter.java:81) ~[?:?]}}
{{ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:?] }}
{{ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:?] }}
{{ at java.lang.Thread.run(Thread.java:748) [?:?]}}

[0]  https://jenkins.opendaylight.org/releng/job/netvirt-csit-1node-openstack-queens-upgrade-fluorine/11/