Quartz works in Grails app three times

I have the following Quartz Job in a Grails application. The task calculates some statistics, as well as sends and e-mails these data. I want the work to be done every day at 7 o’clock.

My problem is that the task is run three times every day, and not just once.

class DailyEmailJob  {
    def eventService 

    static triggers = {
        cron name: 'emailTrigger', cronExpression: "0 0 7 * * ?"
    }

    def execute() {
        eventService.send24StatsEmail()
    }
}

I host a Grails application on Apache Tomcat / 7.0.35 using Grails 2.2.1 and quartz-1.0-RC6