MQTT NIO transport hangup

I'm trying out the MQTT transport and examples available as of version 5.9
(example.Publisher, example.Listener using fusesource mqtt-client)

when activating connector mqtt+nio on broker side, running the Publisher
leads to an infinite loop in class
org.apache.activemq.transport.mqtt.MQTTCodec, method processHeader

it works fine running it with mqtt connector, i.e. it is somehow related to
NIO
has anyone encountered this behavior?

I tried with different JDK version (6, 7) on Windows to exclude some JDK/OS
related issue without success