NPE while shutting down

[anton-johansson]

2018-01-04 20:41:29,649 INFO  com.anton.ehome.Daemon:72 - Stopping daemons...
2018-01-04 20:41:29,659 INFO  com.anton.ehome.zwave.Controller:80 - Stopping Z-Wave controller 'default'
2018-01-04 20:41:29,662 INFO  com.anton.ehome.Daemon:74 - All daemons successfully stopped
2018-01-04 20:41:29,662 INFO  com.anton.ehome.EntryPoint:61 - Exiting...
2018-01-04 20:41:30,186 ERROR com.whizzosoftware.wzwave.channel.ZWaveChannelInboundHandler:81 - An exception occurred
java.lang.NullPointerException
	at com.whizzosoftware.wzwave.controller.netty.NettyZWaveController.onTransactionFailed(NettyZWaveController.java:457)
	at com.whizzosoftware.wzwave.channel.ZWaveChannelInboundHandler.userEventTriggered(ZWaveChannelInboundHandler.java:97)
	at io.netty.channel.AbstractChannelHandlerContext.invokeUserEventTriggered(AbstractChannelHandlerContext.java:304)
	at io.netty.channel.AbstractChannelHandlerContext.fireUserEventTriggered(AbstractChannelHandlerContext.java:290)
	at com.whizzosoftware.wzwave.channel.TransactionInboundHandler$NettyZWaveChannelContext.process(TransactionInboundHandler.java:184)
	at com.whizzosoftware.wzwave.channel.TransactionInboundHandler.processEvent(TransactionInboundHandler.java:135)
	at com.whizzosoftware.wzwave.channel.TransactionInboundHandler.userEventTriggered(TransactionInboundHandler.java:101)
	at com.whizzosoftware.wzwave.channel.TransactionTimeoutHandler.run(TransactionTimeoutHandler.java:44)
	at io.netty.util.concurrent.PromiseTask$RunnableAdapter.call(PromiseTask.java:38)
	at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:123)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:341)
	at io.netty.util.concurrent.SingleThreadEventExecutor.confirmShutdown(SingleThreadEventExecutor.java:640)
	at io.netty.channel.ThreadPerChannelEventLoop.run(ThreadPerChannelEventLoop.java:62)
	at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
	at java.lang.Thread.run(Thread.java:748)