NPE on Backup Client 1.3

2014-08-13 09:09:38,094 INFO  [main] c.a.s.i.b.client.RestStashService Unlocking Stash using token: 63da07b4159738974ff59283cfa69e3fc8e36f0e
2014-08-13 09:09:38,130 ERROR [main] c.a.s.i.backup.client.BackupMain A backup could not be created. Reason: null
java.lang.NullPointerException: null
        at groovy.json.internal.LazyMap.buildIfNeeded(LazyMap.java:113) ~[groovy-all-2.3.6.jar:2.3.6]
        at groovy.json.internal.LazyMap.get(LazyMap.java:98) ~[groovy-all-2.3.6.jar:2.3.6]
        at com.atlassian.stash.internal.backup.client.json.JsonMaintenanceStatus.getLatestTask(JsonMaintenanceStatus.groovy:17) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.layout.DefaultStashHome.archive(DefaultStashHome.groovy:93) ~[stash-backup-core-1.3.0.jar:na]
        at com.atlassian.stash.internal.backup.client.DefaultBackupClient.archiveHome(DefaultBackupClient.groovy:82) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.FixedRateProgressPublisher.publishWhileExecuting(FixedRateProgressPublisher.groovy:34) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.RestStashService.backup(RestStashService.groovy:66) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.RestStashService.lock(RestStashService.groovy:174) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.DefaultBackupClient.backup(DefaultBackupClient.groovy:50) ~[stash-backup-client.jar:1.3.0]
        at com.atlassian.stash.internal.backup.client.spring.SpringMain.run(SpringMain.groovy:28) [stash-backup-core-1.3.0.jar:na]
        at com.atlassian.stash.internal.backup.client.spring.SpringMain.run(SpringMain.groovy) [stash-backup-core-1.3.0.jar:na]
        at com.atlassian.stash.internal.backup.client.BackupMain.main(BackupMain.groovy:38) [stash-backup-client.jar:1.3.0]
        ... 137 frames suppressed

2014-08-13 09:09:38,085 ERROR [threadpool:thread-18366] backup_user 549x239508x0 1xo6p2e 10.10.50.27,127.0.0.1 "POST /mvc/admin/backups HTTP/1.1" c.a.e.i.AsynchronousAbleEventDispatcher There was an exception thrown trying to dispatch event [com.atlassian.johnson.event.RemoveEvent[source=com.atlassian.stash.internal.maintenance.DefaultMaintenanceModeHelper@6efe63ec]] from the invoker [SingleParameterMethodListenerInvoker{method=public void com.atlassian.webhooks.plugin.WebHookEventsProcessor.onEvent(java.lang.Object), listener=com.atlassian.webhooks.plugin.WebHookEventsProcessor@1952acf}]
java.lang.RuntimeException: attempt to unlock read lock, not locked by current thread
	at com.atlassian.event.internal.SingleParameterMethodListenerInvoker.invoke(SingleParameterMethodListenerInvoker.java:54) ~[atlassian-event-2.3.5.jar:na]
	at com.atlassian.event.internal.AsynchronousAbleEventDispatcher$1$1.run(AsynchronousAbleEventDispatcher.java:48) ~[atlassian-event-2.3.5.jar:na]
	at com.google.common.util.concurrent.MoreExecutors$SameThreadExecutorService.execute(MoreExecutors.java:253) [guava-11.0.2-atlassian-01.jar:na]
	at com.atlassian.event.internal.AsynchronousAbleEventDispatcher.dispatch(AsynchronousAbleEventDispatcher.java:107) [atlassian-event-2.3.5.jar:na]
	at com.atlassian.stash.internal.event.LockFreeEventPublisher$Publisher.dispatch(LockFreeEventPublisher.java:201) [stash-platform-3.0.4.jar:na]
	at com.atlassian.stash.internal.event.LockFreeEventPublisher.publish(LockFreeEventPublisher.java:75) [stash-platform-3.0.4.jar:na]
	at com.atlassian.stash.internal.event.TransactionAwareEventPublisher.publish(TransactionAwareEventPublisher.java:84) [stash-platform-3.0.4.jar:na]
	at com.atlassian.stash.internal.maintenance.DefaultMaintenanceModeHelper.unlock(DefaultMaintenanceModeHelper.java:38) [stash-service-impl-3.0.4.jar:na]
	at com.atlassian.stash.internal.maintenance.MaintenanceModePhase.run(MaintenanceModePhase.java:29) [stash-service-impl-3.0.4.jar:na]
	at com.atlassian.stash.internal.maintenance.backup.AbstractBackupTask.run(AbstractBackupTask.java:84) [stash-service-impl-3.0.4.jar:na]
	at com.atlassian.stash.internal.maintenance.DefaultMaintenanceTaskMonitor.run(DefaultMaintenanceTaskMonitor.java:169) [stash-service-impl-3.0.4.jar:na]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [na:1.7.0_55]
	at java.util.concurrent.FutureTask.run(FutureTask.java:262) [na:1.7.0_55]
	at com.atlassian.stash.internal.concurrent.StateTransferringExecutor$StateTransferringRunnable.run(StateTransferringExecutor.java:69) [stash-platform-3.0.4.jar:na]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) [na:1.7.0_55]
	at java.util.concurrent.FutureTask.run(FutureTask.java:262) [na:1.7.0_55]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178) [na:1.7.0_55]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292) [na:1.7.0_55]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_55]
	at java.lang.Thread.run(Thread.java:744) [na:1.7.0_55]
	... 1 frame trimmed
Caused by: java.lang.IllegalMonitorStateException: attempt to unlock read lock, not locked by current thread
	at java.util.concurrent.locks.ReentrantReadWriteLock$Sync.unmatchedUnlockException(ReentrantReadWriteLock.java:447) ~[na:1.7.0_55]
	at java.util.concurrent.locks.ReentrantReadWriteLock$Sync.tryReleaseShared(ReentrantReadWriteLock.java:431) ~[na:1.7.0_55]
	at java.util.concurrent.locks.AbstractQueuedSynchronizer.releaseShared(AbstractQueuedSynchronizer.java:1340) ~[na:1.7.0_55]
	at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.unlock(ReentrantReadWriteLock.java:883) ~[na:1.7.0_55]
	at com.atlassian.webhooks.plugin.OsgiWebHookProviderWebHookRegistry.getWebHooks(OsgiWebHookProviderWebHookRegistry.java:103) ~[na:na]
	at com.atlassian.webhooks.plugin.OsgiWebHookProviderWebHookRegistry.getWebHooks(OsgiWebHookProviderWebHookRegistry.java:37) ~[na:na]
	at com.atlassian.webhooks.plugin.DelegatingWebHookRegistry$2.apply(DelegatingWebHookRegistry.java:40) ~[na:na]
	at com.atlassian.webhooks.plugin.DelegatingWebHookRegistry$2.apply(DelegatingWebHookRegistry.java:36) ~[na:na]
	at com.google.common.collect.Iterators$8.next(Iterators.java:812) ~[guava-11.0.2-atlassian-01.jar:na]
	at com.google.common.collect.Iterables$3.next(Iterables.java:508) ~[guava-11.0.2-atlassian-01.jar:na]
	at com.google.common.collect.Iterables$3.next(Iterables.java:501) ~[guava-11.0.2-atlassian-01.jar:na]
	at com.google.common.collect.Iterators$5.hasNext(Iterators.java:544) ~[guava-11.0.2-atlassian-01.jar:na]
	at com.atlassian.webhooks.plugin.WebHookEventsProcessor.doOnEvent(WebHookEventsProcessor.java:37) ~[na:na]
	at com.atlassian.webhooks.plugin.WebHookEventsProcessor.onEvent(WebHookEventsProcessor.java:32) ~[na:na]
	at com.atlassian.event.internal.SingleParameterMethodListenerInvoker.invoke(SingleParameterMethodListenerInvoker.java:36) ~[atlassian-event-2.3.5.jar:na]
	... 20 common frames omitted