getFieldValues doesn't work on 1 item selected

From the Cash Sale form button, my code loads the current Customer record and adds certain items to a Multi Select List. (highlights them)

When I load the Customer Record and the Multi Select list on the Customer record has 2 or more items already selected on it, it works fine.

When I load the Customer Record and the Multi Select list on the Customer record has only 1 item, the code doesn't update the list.

function xUpdateBadges()  {   <span style="color:'"SeaGreen"'">//**Get Data from Customer record </span>   var record = nlapiLoadRecord('customer', nlapiGetFieldValue('entity'));   var GFV = new Array;   GFV = record.getFieldValues('custentity_badges_earned');<span style="color:'"SeaGreen"'">//Multi Select</span>   for(var i=0; i&amp;lt;= GFV.length; i++)   {    //alert(i + ": " + GFV[i]); <span style="color:'"Purple"'">//When only 1 item is selected GFV[i] returns 'undefined'</span>   }   GFV[i+1] = '6'; //another item to select   GFV[i+2] = '7'; //another item to select      <span style="color:'"SeaGreen"'">//**Committ the changes to the Supporter record</span>    record.setFieldValues('custentity_badges_earned', GFV);   var id = nlapiSubmitRecord(record, true);   alert("All Done");  }