user_bulk_download.php

Instaed of $v->name it should be $v-shortname

 if ($extrafields = get_records_select('user_info_field')) {
   foreach ($extrafields as $n=>$v){
     $fields['profile_field_'.$v->shortname] = 'profile_field_'.$v->name;
   }
 }

It should be

 if ($extrafields = get_records_select('user_info_field')) {
   foreach ($extrafields as $n=>$v){
     $fields['profile_field_'.$v->shortname] = 'profile_field_'.$v->shortname;
   }
 }


Error and solution found by Lars Kobbe