Netsuite: Workflow action script

The following script is executed after clicking a button on sales order. It creates work orders for items on the sales order if some conditions are fulfilled. It works fine, but sometimes it stops working and I need to undeploy and deploy the script again for it to work. Do you know what can cause this behaviour?

/**
 * @NApiVersion 2.x
 * @NScriptType workflowactionscript
 */
define(['N/record', 'N/search'],        
        
    function(record, search) {
        var scriptName = "createWO";
        "use strict";           

        function onAction (context) {
            var funcName = scriptName + "onAction " + context.newRecord.type + " " + context.newRecord.id;
            log.debug(funcName, "Starting");
            
        try {
            
        /**Getting values from SO.
         */
                    var currentRecord = context.newRecord;
                    
                    var so = currentRecord.getValue({
                    fieldId: 'id'
                    });
                        

        
        var s = search.create({
            type : search.Type.TRANSACTION,
               columns:
               [
                  search.createColumn({name: "item"}),
                  search.createColumn({name: "formulanumeric", formula: "({quantity}-NVL({quantitycommitted},0))-nvl({quantityshiprecv},0)"})
               ],
            filters:
            [
                ["type","anyof","SalesOrd"], 
                "AND", 
                ["mainline","is","F"], 
                "AND", 
                ["internalidnumber","equalto",so], 
                "AND", 
                ["taxline","is","F"], 
                "AND", 
                ["shipping","is","F"], 
                "AND", 
                ["item.type","anyof","Assembly"], 
                "AND", 
                ["formulanumeric: ({quantity}-NVL({quantitycommitted},0))-nvl({quantityshiprecv},0)","greaterthan","0"]
            ]
        });


        var searchResultCount = s.runPaged().count;
        log.debug("s result count",searchResultCount);
        s.run().each(function(result){
           // .run().each has a limit of 4,000 results
           return true;
        });
        
        var searchResult = s.run().getRange({start:0,end:999});
        
    for(var j=0;j<searchResultCount;j++) {
        
            var item = searchResult[j].getValue({name:'item'});
            var qtytobuild = searchResult[j].getValue({name:'formulanumeric'});
            
    
                            
                            var TO = record.create({
                            type: 'workorder',
                            isDynamic:true
                            });                     
                            
                            TO.setValue({
                            fieldId: 'customform', 
                            value: '50'
                            });
                            
                            TO.setValue({
                            fieldId:'subsidiary', 
                            value: 1
                            });                         
                            
                            TO.setValue({
                            fieldId: 'location', 
                            value: 2
                            });
                            
                            
                            TO.setValue({
                            fieldId: 'assemblyitem', 
                            value: item
                            });
                            
                            TO.setValue({
                            fieldId: 'quantity', 
                            value: qtytobuild
                            });
                            
                            var newWO = TO.save({                  
                            ignoreMandatoryFields: true    
                            });
                            
                            
                
    }
                
                                
                                
            } catch (e) {
                log.error(funcName + "Unable to create WO", e)
            }           
        }

    return {
        onAction : onAction
    };
    
});