为什么 quartz 执行 scheduleJob()，有时候会执行多次啊？

public class QuartzStudy implements Job {
    @Override
    public void execute(JobExecutionContext jobExecutionContext) {
        System.out.println(jobExecutionContext.getJobDetail().getKey().getName() + "-" + Thread.currentThread().getName() + "-" + Thread.currentThread().getId() + "-" + new Date());
    }

    private static SchedulerFactory schedulerFactory = new StdSchedulerFactory();
    private static Scheduler scheduler;
    static {
        try {
            scheduler = schedulerFactory.getScheduler();
            scheduler.start();
        } catch (SchedulerException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws SchedulerException, InterruptedException {
        JobDetail jobDetail = JobBuilder.newJob(QuartzStudy.class).withIdentity("job1").build();
        CronTrigger trigger = TriggerBuilder.newTrigger()
                .withSchedule(CronScheduleBuilder.cronSchedule("*/5 * * * * ?").withMisfireHandlingInstructionIgnoreMisfires())
                .build();
        scheduler.scheduleJob(jobDetail, trigger);
        Thread.sleep(10000);
        scheduler.pauseJob(jobDetail.getKey());
    }
}

这个的执行结果难道不该是 10 秒的时间打印 2 次，然后就暂停了么为什么有时候会打印 2 次，有时候会打印 3 次出来？

job1-DefaultQuartzScheduler_Worker-1-14-Thu Jan 03 09:34:45 CST 2019
job1-DefaultQuartzScheduler_Worker-2-15-Thu Jan 03 09:34:50 CST 2019
job1-DefaultQuartzScheduler_Worker-3-16-Thu Jan 03 09:34:55 CST 2019

job1-DefaultQuartzScheduler_Worker-1-14-Thu Jan 03 09:40:45 CST 2019
job1-DefaultQuartzScheduler_Worker-2-15-Thu Jan 03 09:40:50 CST 2019