• create a pipeline Job with dynamic gerrit triggers
• open "Configure" again and save again (important)

• restart Jenkins

• you'll get a NPE loading the job:

WARNING: Frank-pipeline-test-trigger
java.lang.NullPointerException
at com.sonyericsson.hudson.plugins.gerrit.trigger.hudsontrigger.GerritTrigger.cancelTimer(GerritTrigger.java:553)
at com.sonyericsson.hudson.plugins.gerrit.trigger.hudsontrigger.GerritTrigger.stop(GerritTrigger.java:629)
at org.jenkinsci.plugins.workflow.job.properties.PipelineTriggersJobProperty.stopTriggers(PipelineTriggersJobProperty.java:93)
at org.jenkinsci.plugins.workflow.job.WorkflowJob.onLoad(WorkflowJob.java:149)
at hudson.model.Items.load(Items.java:333)
at jenkins.model.Jenkins$17.run(Jenkins.java:2823)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:998)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

the problem is the <gerritTriggerTimerTask> node in the job's config.xml:

• When you freshly create the pipeline job (including dynamic trigger settings), the xml-node is not there and the job is loading correctly, even when restarting jenkins
• as soon as you re-save the job config, the <gerritTriggerTimerTask> node is inserted in the job's xml and now on the next Jenkins restart the job fails to load with an NPE as stated above
• if you don't restart the jenkins, the job keeps working and is still editable, also dynamic triggers work, but as soon as you restart jenkins, the job is no longer accessible
• if you manually remove the <gerritTriggerTimerTask> node in the job's config.xml in the jenkins backend and restart jenkins, the job becomes available again (until the next save + restart)