MessageListener behaves in an odd way

bug exists in release for Maven

org.eclipse.paho
org.eclipse.paho.client.mqttv3
1.2.0

MqttClient client = new MqttClient(broker, clientId, persistence);

client.setCallback(new HHACallBack());

MqttConnectOptions options = new MqttConnectOptions();
options.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);

client.connect(options);

client.subscribe("#", new TopicMessageListener());
client.subscribe("$SYS/#", new SystemTopicMessageListener());

The class TopicMessageListener subscribed to "#" receives as well "$SYS/#" so it seems those aren't properly filtered.