Program: 149424
Project: 149424
Buggy source:
@Override public boolean shouldSchedule(Queue.Task p,List<Action> actions){
  if (p instanceof AbstractProject && p instanceof Project) {
    AbstractProject project=(AbstractProject)p;
    InstanceCreator instanceCreator=null;
    boolean singleUse=false;
    for (    Object buildWrapper : ((Project)p).getBuildWrappers().values()) {
      if (buildWrapper instanceof InstanceCreator) {
        instanceCreator=(InstanceCreator)buildWrapper;
      }
 else       if (buildWrapper instanceof SingleUseSlaveBuildOption) {
        singleUse=true;
      }
      if (instanceCreator != null && singleUse) {
        break;
      }
    }
    if (instanceCreator != null) {
      Queue.Item queueItem=Queue.getInstance().getItem(p);
      if (queueItem != null && queueItem.getAssignedLabel() != null) {
        return false;
      }
      LabelAtom label=ElasticBoxLabelFinder.getLabel(instanceCreator.getProfile(),singleUse);
      if (singleUse) {
        try {
          ElasticBoxSlave slave=new ElasticBoxSlave(UUID.randomUUID().toString(),singleUse);
          slave.setProfileId(instanceCreator.getProfile());
          slave.setCloud(ElasticBoxCloud.getInstance());
          slave.setInUse(true);
          Jenkins.getInstance().addNode(slave);
          ElasticBoxSlaveHandler.submit(slave);
        }
 catch (        Descriptor.FormException ex) {
          Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
        }
catch (        IOException ex) {
          Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
        }
      }
      try {
        project.setAssignedLabel(label);
      }
 catch (      IOException ex) {
        Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
      }
    }
  }
  return true;
}

Fixed version (ground truth):
@Override public boolean shouldSchedule(Queue.Task p,List<Action> actions){
  if (p instanceof AbstractProject && p instanceof Project) {
    AbstractProject project=(AbstractProject)p;
    InstanceCreator instanceCreator=null;
    boolean singleUse=false;
    for (    Object buildWrapper : ((Project)p).getBuildWrappers().values()) {
      if (buildWrapper instanceof InstanceCreator) {
        instanceCreator=(InstanceCreator)buildWrapper;
      }
 else       if (buildWrapper instanceof SingleUseSlaveBuildOption) {
        singleUse=true;
      }
      if (instanceCreator != null && singleUse) {
        break;
      }
    }
    if (instanceCreator != null) {
      Queue.Item queueItem=Queue.getInstance().getItem(p);
      if (queueItem != null && queueItem.getAssignedLabel() != null) {
        return false;
      }
      LabelAtom label=ElasticBoxLabelFinder.getLabel(instanceCreator.getProfile(),singleUse);
      if (singleUse) {
        try {
          ElasticBoxSlave slave=new ElasticBoxSlave(instanceCreator.getProfile(),singleUse,ElasticBoxCloud.getInstance());
          slave.setInUse(true);
          Jenkins.getInstance().addNode(slave);
          ElasticBoxSlaveHandler.submit(slave);
        }
 catch (        Descriptor.FormException ex) {
          Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
        }
catch (        IOException ex) {
          Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
        }
      }
      try {
        project.setAssignedLabel(label);
      }
 catch (      IOException ex) {
        Logger.getLogger(InstanceCreationQueueDecisionHandler.class.getName()).log(Level.SEVERE,ex.getMessage(),ex);
      }
    }
  }
  return true;
}