Consistently over the past 24 hours, whenever triggering a build (or rebuilding the last build), the following happens:
```
00:00:00.013 Notifying endpoint 'HTTP:http://127.0.0.1:8001/jenkins_endpoint'
00:00:00.022 ERROR: Failed to notify endpoint 'HTTP:http://127.0.0.1:8001/jenkins_endpoint'
00:00:00.022 java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
00:00:00.022 at java.util.LinkedList.checkElementIndex(LinkedList.java:553)
00:00:00.022 at java.util.LinkedList.set(LinkedList.java:488)
00:00:00.022 at hudson.model.Run.getLog(Run.java:1981)
00:00:00.022 at com.tikal.hudson.plugins.notification.Phase.getLog(Phase.java:141)
00:00:00.023 at com.tikal.hudson.plugins.notification.Phase.buildJobState(Phase.java:79)
00:00:00.023 at com.tikal.hudson.plugins.notification.Phase.handle(Phase.java:42)
00:00:00.023 at com.tikal.hudson.plugins.notification.JobListener.onStarted(JobListener.java:31)
00:00:00.023 at hudson.model.listeners.RunListener.fireStarted(RunListener.java:213)
00:00:00.023 at hudson.model.Run.execute(Run.java:1755)
00:00:00.023 at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
00:00:00.024 at hudson.model.ResourceController.execute(ResourceController.java:89)
00:00:00.024 at hudson.model.Executor.run(Executor.java:240)
00:00:00.024 Failed to notify endpoint 'HTTP:http://127.0.0.1:8001/jenkins_endpoint' - java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
00:00:00.047 Building remotely on integration-slave1405 (phpflavor-hhvm contintLabsSlave UbuntuTrusty) in workspace /mnt/jenkins-workspace/workspace/mediawiki-core-qunit-karma
```
It does not cause the build to fail but is concerning nonetheless.
Presumably this is another one of those environment variables Zuul uses from Jenkins Job Builder that is not saved in the Build Parameters. However, contrary to those, this previously worked fine.
Probably caused by upstream Jenkins or Zuul which have both recently been upgraded.