Intermittent duplicates during client failover in a network of brokers

Issue

• We have just applied the latest 6.0.0 Rollup package and we are seeing various messages being thrown into the DLQ AND being delivered to the client via durable subscriptions. This appears to be
  happening on various connected Java clients who are all set to AutoAcknowledge.
  The uri we are using for each client is: failover:(tcp://amq-broker-1:61616,tcp://amq-broker-2:61616)?jms.watchTopicAdvisories=false