Lots of duplicate ActiveMQ messages stay in the queue (?)

mmeinhold@jira-bamboo:/etc/service/bamboo-server/log/logs$ zgrep "ActiveMQ BrokerService" @400000005433d75c1c0295ec.s 
2014-10-07 11:40:59,467 INFO [ActiveMQ BrokerService[bamboo] Task-34655] [TempQueue] temp-queue://ID:ip-172-30-147-214-57871-1412639319561-1:1:1 on dispose, purge of 1 pending messages: org.apache.activemq.broker.region.cursors.VMPendingMessageCursor@73d93bfa
2014-10-07 11:57:24,238 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [AbstractStoreCursor] org.apache.activemq.broker.region.cursors.QueueStorePrefetch@467d603a:com.atlassian.bamboo.buildTailQueue,batchResetNeeded=false,storeHasMessages=true,size=1,cacheEnabled=true,maxBatchSize:2,hasSpace:true - cursor got duplicate: ID:ip-172-30-146-28-53258-1412639445366-1:1:9:1:33161, 4
2014-10-07 11:57:24,238 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [Queue] duplicate message from store ID:ip-172-30-146-28-53258-1412639445366-1:1:9:1:33161, redirecting for dlq processing
2014-10-07 11:57:24,262 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [AbstractStoreCursor] org.apache.activemq.broker.region.cursors.QueueStorePrefetch@467d603a:com.atlassian.bamboo.buildTailQueue,batchResetNeeded=false,storeHasMessages=true,size=1,cacheEnabled=true,maxBatchSize:2,hasSpace:true - cursor got duplicate: ID:ip-172-30-144-159-47160-1412639319990-1:1:9:1:34668, 4
2014-10-07 11:57:24,262 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [Queue] duplicate message from store ID:ip-172-30-144-159-47160-1412639319990-1:1:9:1:34668, redirecting for dlq processing
2014-10-07 11:57:24,268 WARN [ActiveMQ BrokerService[bamboo] Task-35320] [AbstractStoreCursor] org.apache.activemq.broker.region.cursors.QueueStorePrefetch@467d603a:com.atlassian.bamboo.buildTailQueue,batchResetNeeded=false,storeHasMessages=true,size=1,cacheEnabled=true,maxBatchSize:2,hasSpace:true - cursor got duplicate: ID:agent-07-02-45716-1412646530061-1:1:10:1:29947, 4
2014-10-07 11:57:24,268 WARN [ActiveMQ BrokerService[bamboo] Task-35320] [Queue] duplicate message from store ID:agent-07-02-45716-1412646530061-1:1:10:1:29947, redirecting for dlq processing
2014-10-07 11:57:24,311 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [AbstractStoreCursor] org.apache.activemq.broker.region.cursors.QueueStorePrefetch@467d603a:com.atlassian.bamboo.buildTailQueue,batchResetNeeded=false,storeHasMessages=true,size=1,cacheEnabled=true,maxBatchSize:2,hasSpace:true - cursor got duplicate: ID:agent-07-02-45716-1412646530061-1:1:10:1:29948, 4
2014-10-07 11:57:24,311 WARN [ActiveMQ BrokerService[bamboo] Task-35318] [Queue] duplicate message from store ID:agent-07-02-45716-1412646530061-1:1:10:1:29948, redirecting for dlq processing
2014-10-07 11:57:24,319 WARN [ActiveMQ BrokerService[bamboo] Task-35320] [AbstractStoreCursor] org.apache.activemq.broker.region.cursors.QueueStorePrefetch@467d603a:com.atlassian.bamboo.buildTailQueue,batchResetNeeded=false,storeHasMessages=true,size=1,cacheEnabled=true,maxBatchSize:2,hasSpace:true - cursor got duplicate: ID:ip-172-30-144-218-58062-1412653895028-1:1:10:1:25659, 4
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