Script-based validator runs 3 times on a save?

I have a semi-simple script-based validator, which I have set on both the OwnedBy and the FiledAgainst attributes on a task.  I (eventually) will do validation that if OwnedBy is not Unassigned (so someone owns it), the FiledAgainst attribute can not be "Backlog" (which is our default which means it isn't in any team yet).

I have the script written and running.  I have confirmed that it only runs when I change one of the two fields (FiledAgainst or OwnedBy) and not when things like Priority are changed, which is good.

However, if I change JUST the OwnedBy attribute and click Save, it looks like my Script is run 3 times, based on the console.log messages that I have in the script.  As it starts, I log the values of the 2 attributes, and then if the OwnedBy is Unassigned (based on the UUID), I log a 3rd message.  I did a single save of just changing the OwnedBy attribute and you can see, I get 3 sets of my 3 message lines.  Is there a reason why it runs 3 times???

the Log messages:
!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:45.513
!MESSAGE LOG: _YNh4MOlsEdq4xpiOKg5hvA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:45.517
!MESSAGE LOG: _jMF98OkHEeKDodPdruloFA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:45.522
!MESSAGE LOG: Unassigned Owner

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:46.554
!MESSAGE LOG: _YNh4MOlsEdq4xpiOKg5hvA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:46.557
!MESSAGE LOG: _jMF98OkHEeKDodPdruloFA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:46.561
!MESSAGE LOG: Unassigned Owner

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:47.394
!MESSAGE LOG: _YNh4MOlsEdq4xpiOKg5hvA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:47.398
!MESSAGE LOG: _jMF98OkHEeKDodPdruloFA

!ENTRY com.ibm.team.rtc.common.scriptengine 1 0 2013-07-10 14:02:47.402
!MESSAGE LOG: Unassigned Owner


The script:
dojo.provide("com.ibm.ws.team.rtc.attribcustom.validators.CheckFiledAgainst");
dojo.require("com.ibm.team.workitem.api.common.WorkItemAttributes");
dojo.require("com.ibm.team.workitem.api.common.Status");

(function() {
    var WorkItemAttributes = com.ibm.team.workitem.api.common.WorkItemAttributes;
    var Status= com.ibm.team.workitem.api.common.Status;
       dojo.declare("com.ibm.ws.team.rtc.attribcustom.validators.CheckFiledAgainst", null, {

    validate: function(attributeId, workItem, configuration) {
        console.log(workItem.getValue(WorkItemAttributes.OWNER));
        console.log(workItem.getValue(WorkItemAttributes.FILED_AGAINST));
       
        //Note:  OwnedBy=Unassigned maps to UUID _YNh4MOlsEdq4xpiOKg5hvA
        var unassignedOwner = "_YNh4MOlsEdq4xpiOKg5hvA";
        if (workItem.getValue(WorkItemAttributes.OWNER) === unassignedOwner) {
            console.log('Unassigned Owner');
            return Status.OK_STATUS;
        }
       
        else {
                    console.log('validate here!');
                //var severity= configuration.getChild("parameters").getStringDefault("severity", Severity.ERROR.name);
                //var message= configuration.getChild("parameters").getStringDefault("message", "");
                //return new Status(Severity[severity], message);
                return Status.OK_STATUS;
            }
    }
});
})();