Happened after a while of inactivity (if that matters).
Was inactive for a while, then I started typing.
IIRC NPE occured after <Tab>.

[standalone@localhost:9999 interface=public] cd ..
[standalone@localhost:9999 /] cd ..
[standalone@localhost:9999 /] ls
extension core-service path subsystem system-property deployment interface socket-binding-group
[standalone@localhost:9999 /] Exception in thread "pool-1-thread-21" java.lang.NullPointerException
at org.xnio.channels.TranslatingSuspendableChannel.scheduleReadTask(TranslatingSuspendableChannel.java:253)
at org.xnio.channels.TranslatingSuspendableChannel.resumeReads(TranslatingSuspendableChannel.java:233)
at org.jboss.remoting3.remote.ClientConnectionOpenListener$Authentication$2.run(ClientConnectionOpenListener.java:498)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)