I've run into an issue where, when trying to trigger a pipeline job from a freestyle (classic), I'm seeing a NPE in the jenkins log. This happens when the pipeline job is an upstream of a freestyle job; and trying to watch for new builds of the freestyle.

The full stack trace is:

WARNING: RunListener failed
java.lang.NullPointerException
        at hudson.model.Result.isBetterOrEqualTo(Result.java:130)
        at jenkins.triggers.ReverseBuildTrigger.shouldTrigger(ReverseBuildTrigger.java:139)
        at jenkins.triggers.ReverseBuildTrigger.access$000(ReverseBuildTrigger.java:89)
        at jenkins.triggers.ReverseBuildTrigger$RunListenerImpl.onCompleted(ReverseBuildTrigger.java:258)
        at hudson.model.listeners.RunListener.fireCompleted(RunListener.java:214)
        at hudson.model.Run.execute(Run.java:1765)
        at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
        at hudson.model.ResourceController.execute(ResourceController.java:98)
        at hudson.model.Executor.run(Executor.java:401)


This is preventing the upstream job from getting triggered.