Sliding Time Window: Performance problem

"main@1" prio=5 tid=0x1 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
      at java.util.PriorityQueue.indexOf(PriorityQueue.java:357)
      at java.util.PriorityQueue.remove(PriorityQueue.java:376)
      at org.drools.core.rule.SlidingTimeWindow$SlidingTimeWindowContext.remove(SlidingTimeWindow.java:285)
      at org.drools.core.rule.SlidingTimeWindow.retractFact(SlidingTimeWindow.java:157)
      at org.drools.core.rule.BehaviorManager.retractFact(BehaviorManager.java:99)
      at org.drools.core.reteoo.WindowNode.retractRightTuple(WindowNode.java:157)
      at org.drools.core.reteoo.RightTupleImpl.retractTuple(RightTupleImpl.java:262)
      at org.drools.core.reteoo.ObjectTypeNode.lambda$retractRightTuples$2(ObjectTypeNode.java:337)
      at org.drools.core.reteoo.ObjectTypeNode$$Lambda$176.793618227.accept(Unknown Source:-1)
      at org.drools.core.common.DefaultFactHandle$SingleLinkedTuples.forEachRightTuple(DefaultFactHandle.java:694)
      at org.drools.core.common.DefaultFactHandle.forEachRightTuple(DefaultFactHandle.java:914)
      at org.drools.core.reteoo.ObjectTypeNode.retractRightTuples(ObjectTypeNode.java:337)
      at org.drools.kiesession.agenda.DefaultAgenda.doRetract(DefaultAgenda.java:1345)
      at org.drools.kiesession.agenda.DefaultAgenda.flushExpirations(DefaultAgenda.java:1336)
      at org.drools.kiesession.agenda.DefaultAgenda.fireLoop(DefaultAgenda.java:757)
      at org.drools.kiesession.agenda.DefaultAgenda.internalFireAllRules(DefaultAgenda.java:694)
      at org.drools.kiesession.agenda.DefaultAgenda.fireAllRules(DefaultAgenda.java:686)
      at org.drools.kiesession.session.StatefulKnowledgeSessionImpl.internalFireAllRules(StatefulKnowledgeSessionImpl.java:1092)
      at org.drools.kiesession.session.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1083)
      at org.drools.kiesession.session.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:1067)