Indexing Job for Custom Fields of Profile Elements Fails

java.lang.NullPointerException
2017-07-10 11:18:30,987 Caesium-2-4 ERROR ServiceRunner [c.a.scheduler.core.JobLauncher] Scheduled job with ID 'User Profile Field Re-Indexer' failed
at java.lang.Thread.run(Thread.java:748)
at com.atlassian.scheduler.caesium.impl.SchedulerQueueWorker.run(SchedulerQueueWorker.java:34)
at com.atlassian.scheduler.caesium.impl.SchedulerQueueWorker.executeNextJob(SchedulerQueueWorker.java:59)
at com.atlassian.scheduler.caesium.impl.SchedulerQueueWorker.executeJob(SchedulerQueueWorker.java:65)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService$1.consume(CaesiumSchedulerService.java:282)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService$1.consume(CaesiumSchedulerService.java:285)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService.executeQueuedJob(CaesiumSchedulerService.java:390)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService.executeClusteredJobWithRecoveryGuard(CaesiumSchedulerService.java:462)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService.executeClusteredJob(CaesiumSchedulerService.java:438)
at com.atlassian.scheduler.caesium.impl.CaesiumSchedulerService.launchJob(CaesiumSchedulerService.java:443)
at com.atlassian.scheduler.core.JobLauncher.launch(JobLauncher.java:97)
at com.atlassian.scheduler.core.JobLauncher.launchAndBuildResponse(JobLauncher.java:118)
at com.atlassian.scheduler.core.JobLauncher.runJob(JobLauncher.java:153)
at de.communardo.jira.plugins.userprofile.utils.JobStarter.runJob(JobStarter.java:93)
at de.communardo.jira.plugins.userprofile.customfield.UpjFieldReindexJob.runJob(UpjFieldReindexJob.java:28)
at de.communardo.jira.plugins.userprofile.customfield.UpjFieldManagerImpl.processSavedUserProfilesUpdates(UpjFieldManagerImpl.java:222)
at de.communardo.jira.plugins.userprofile.customfield.UpjFieldManagerImpl.getUniqueProfileElements(UpjFieldManagerImpl.java:366)