Steps to reproduce the issue

Request new password /?option=com_users&view=reset

Expected result

custom fields not deleted

Actual result

custom fields deleted

System information (as much as possible)

joomla 3.8, php 5.6

Additional comments

thats bug fix /plugins/system/fields/fields.php

function onUserAfterSave

add 'request' in array to this place in code

$task = JFactory::getApplication()->input->getCmd('task');

if (in_array($task, array('activate', 'block', 'unblock', 'request')))
{
return true;
}