smack-4.1.0-beta2: Timeout on publish PayloadItem containing JSON

Problem

When publishing node.send(..), where PayloadItem contains JSON,  the LeafNode's send method   throws org.jivesoftware.smack.SmackException$NoResponseException: No response received within packet reply timeout. Timeout was 5000ms (~5s). 

I did try setPacketReplyTimeout(5000 * 10) but this just made waiting to get same exception longer. 

Details

• Node is a simple instant node, not using ConfigureForm. 
• Subscriber  (not shown below) is on a different thread of control with different connection and he is waiting with a NodeConfigureListener handler...
• jsonObject is ~ 5 megabyte and validates with JSONParser.parse
• Using smack-4.1.0-beta2-SNAPSHOT-2015-01-14
• Using ejabberd 14.12 community

//...

assertNotNull(con);

assertNotNull(jsonObject);

// Create a pubsub manager using an existing connection that is valid
PubSubManager mgr = new PubSubManager(con);

// Get the node that was previously created
LeafNode node = mgr.getNode("testNode");

//Create JSON payload

JsonPacketExtension jasonPacketExtension = new JsonPacketExtension(jsonObject.toString());

PayloadItem  payloadItem = new PayloadItem(jasonPacketExtension);  // no client id, just let server create id

// Publish an Item with JSON payload

node.send(payloadItem); //<================ NoResponseException: No response received within packet reply timeout.