Ниже $arFieldsCopy = $arFields; добавьте
unset($arFieldsCopy['ID'], $arFieldsCopy['TMP_ID'], $arFieldsCopy['WF_LAST_HISTORY_ID'], $arFieldsCopy['SHOW_COUNTER'], $arFieldsCopy['SHOW_COUNTER_START']);
unset($arFieldsCopy['ID'], $arFieldsCopy['TMP_ID'], $arFieldsCopy['WF_LAST_HISTORY_ID'], $arFieldsCopy['SHOW_COUNTER'], $arFieldsCopy['SHOW_COUNTER_START']);