I am trying to create a trigger that would add a new value to a related list if a value is adeded to a field.

The field is called Reason of Contact (ROC) and when ever a new reason of contact is added or the field is populated it brings the new value to the related list in the Case. This is working correctly but when ever the first reason of contact is added to the case this value is entered twice. But after that everything works fine. So can someone see what is wrong with the code so that it would not create a duplicate value if the list for Reason Of Contacts (ROCs) is empty.

//


trigger createROCchildonCaseUpdate on Case (after update) {

// Create an empty list of String
List<Reasons_of_Contact__c> ROCs = new List<Reasons_of_Contact__c>();

    //For each case processed by the trigger, add a new  

    //ROC record for the specified case.  

    //Note that Trigger.New is a list of all the new positions  

    //that are being created.  

    for (Case newCase : Trigger.new) {
    Case oldCase = Trigger.oldMap.get(newCase.Id);
    if (oldCase.Request_3__c != newCase.Request_3__c | oldCase.Request_3__c != NULL) {

         //Create the new ROC in the related list with the following values
               ROCs.add(new Reasons_of_Contact__c(
                        ProgramCaseLink__c = newCase.Id,
                        Type__c = newCase.Request_3__c,
                        ProgramCommentLookup__c = newCase.Program__c));
        }
    }
    insert ROCs;
}