NullPointerException on "Purge unused snapshots" task

Task Name: Purge unused snapshots
Stack-trace:
java.lang.NullPointerException
    at java.util.Objects.requireNonNull(Objects.java:203)
    at org.sonatype.nexus.repository.maven.tasks.PurgeMavenUnusedSnapshotsTask.isSnapshotRepo(PurgeMavenUnusedSnapshotsTask.java:97)
    at org.sonatype.nexus.repository.maven.tasks.PurgeMavenUnusedSnapshotsTask.appliesTo(PurgeMavenUnusedSnapshotsTask.java:74)
    at com.google.common.collect.Iterators$5.computeNext(Iterators.java:637)
    at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:141)
    at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:136)
    at org.sonatype.nexus.repository.RepositoryTaskSupport.execute(RepositoryTaskSupport.java:73)
    at org.sonatype.nexus.scheduling.TaskSupport.call(TaskSupport.java:100)
    at org.sonatype.nexus.quartz.internal.task.QuartzTaskJob.doExecute(QuartzTaskJob.java:143)
    at org.sonatype.nexus.quartz.internal.task.QuartzTaskJob.execute(QuartzTaskJob.java:106)
    at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
    at org.sonatype.nexus.quartz.internal.QuartzThreadPool.lambda$0(QuartzThreadPool.java:145)
    at org.sonatype.nexus.thread.internal.MDCAwareRunnable.run(MDCAwareRunnable.java:40)
    at org.apache.shiro.subject.support.SubjectRunnable.doRun(SubjectRunnable.java:120)
    at org.apache.shiro.subject.support.SubjectRunnable.run(SubjectRunnable.java:108)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    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:750)