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