Figured it out:
commented out some lines in lib/csvlib.class.php
public function set_filename($dataname, $extension = '.csv') {
$filename = clean_filename($dataname);
//$filename .= clean_filename('-' . gmdate("Ymd_Hi"));
//$filename .= clean_filename("-{$this->delimiter}_separated");
$filename .= $extension;
$this->filename = $filename;
Also in export/grade_export_txt.php
//$downloadfilename = clean_filename("$shortname $strgrades"); Get rid of grades string to shorten up the cvs file.
$downloadfilename = clean_filename("$shortname");