Impex-export in 6.3

Hi Experts,

when i am exporting product data using export query in HAC ,Impex Exports are adding "_null" to the end of localized attribute names in the export header.This was not happening in 5.3 version. Query look like:

$productCatalog=catalog $catalogVersion=Staged $whereclause={TF.code} in('302780', '096-101001', '60108-500-P', '60105-219-P')
"#% impex.setTargetFile( ""productExport.csv"", true, 1, -1 );" INSERT_UPDATE Product;code[unique=true,allownull=true];supplierName;productTitle;creationtime[dateformat=MM/dd/yyyy] "#% impex.exportItemsFlexibleSearch( ""SELECT {TF:PK} FROM {Product as TF}, {Catalog as C}, {CatalogVersion as CV} WHERE {TF:catalog} = {C:PK} AND {TF:catalogversion} = {CV:PK} AND {CV:catalog} = {C:PK} AND {C:id} = '$productCatalog' AND {CV:version} = '$catalogVersion' AND $whereclause"" );"

export row are coming from default language ( localized attributes value are coming from default lang(en) but header are showing _null ) Header are showing like- # code;supplierName_null;productTitle_null;creationtime

Ques:2- Also, before the upgrade when we downloaded the export results they used to save in our downloads folder with the filename of the job (e.g. "dataexport-0000LZXM-ImpEx-Export.zip") now they all save with the same name (e.g. "securemedias.zip")