title: Mosquitto MQTT looping on subscribe
body: <p>I'm using mosquitto as my broker server. And I want to build a cluster of brokers based on the bridge connection.</p>
  
  <p>When I published and then subscribed the topic 'presence', I got endless repeated messages from the three broker servers.</p>
  
  <p>I have three servers, such as: 
  10.80.1.1, 10.80.1.2</p>
  
  <p>and I have the following configuration for each server.</p>
  
  <pre><code>on server 10.80.1.1, the config as the following:
  connection myconn
  address 10.80.1.2:1881
  topic # both
  cleansession true
  try_private false
  bridge_attempt_unsubscribe false
  notifications false
  allow_anonymous true
  start_type automatic
  clientid Bridge3
  
  on server 10.80.1.2, the config as the following:
  connection myconn
  address 10.80.1.1:1883
  topic # both
  cleansession true
  try_private false
  bridge_attempt_unsubscribe false
  notifications false
  allow_anonymous true
  start_type automatic
  clientid Bridge2
  </code></pre>
  
  <p>Who guy could help me to fix this problem.</p>