NPE in AMQPMessage getPriority

2018-10-10 16:20:41,664 WARN  [org.apache.activemq.artemis.core.server] AMQ222151: removing consumer which did not handle a message, consumer=ServerConsumerImpl [id=0, filter=null, binding=LocalQueueBinding 
...
java.lang.RuntimeException
	at org.apache.activemq.artemis.protocol.amqp.broker.AMQPMessage.toCore(AMQPMessage.java:1206) [artemis-amqp-protocol-2.6.1.amq-720004-redhat-1.jar:]
	at org.apache.activemq.artemis.core.protocol.core.impl.CoreSessionCallback.sendMessage(CoreSessionCallback.java:123) [artemis-server-2.6.1.amq-720004-redhat-1.jar:2.6.1.amq-720004-redhat-1]
	at org.apache.activemq.artemis.core.server.impl.ServerConsumerImpl.deliverStandardMessage(ServerConsumerImpl.java:1106) [artemis-server-2.6.1.amq-720004-redhat-1.jar:2.6.1.amq-720004-redhat-1]
        ...
Caused by: java.lang.NullPointerException
	at org.apache.activemq.artemis.protocol.amqp.broker.AMQPMessage.getPriority(AMQPMessage.java:666) [artemis-amqp-protocol-2.6.1.amq-720004-redhat-1.jar:]
	at org.apache.activemq.artemis.protocol.amqp.converter.AmqpCoreConverter.toCore(AmqpCoreConverter.java:192) [artemis-amqp-protocol-2.6.1.amq-720004-redhat-1.jar:]
	at org.apache.activemq.artemis.protocol.amqp.converter.AMQPConverter.toCore(AMQPConverter.java:43) [artemis-amqp-protocol-2.6.1.amq-720004-redhat-1.jar:]
	at org.apache.act