A-MQ7 example message-priority throws "java.lang.IllegalStateException: Priority is broken!" in about 20% of runs

[INFO] Server started
[INFO] 
[INFO] --- artemis-maven-plugin:1.2.0.amq-700006-redhat-1:runClient (runClient) @ message-priority ---
Message sent: first message with priority: 4
Message sent: second messagewith priority: 5
Message sent: third messagewith priority: 9
Received message : [second message]
Received message : [third message]
Received message : [first message]
[ERROR] 
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.activemq.artemis.maven.ArtemisClientPlugin.doExecute(ArtemisClientPlugin.java:61)
	at org.apache.activemq.artemis.maven.ArtemisAbstractPlugin.execute(ArtemisAbstractPlugin.java:75)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: java.lang.IllegalStateException: Priority is broken!
	at org.apache.activemq.artemis.jms.example.MessagePriorityExample.main(MessagePriorityExample.java:97)
	... 28 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 16.813 s
[INFO] Finished at: 2016-05-26T07:55:54+02:00
[INFO] Final Memory: 66M/783M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.activemq:artemis-maven-plugin:1.2.0.amq-700006-redhat-1:runClient (runClient) on project message-priority: null: MojoFailureException -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.