Try this,
$( document ).ready( function() {
$('.cpf').mask('999.999.999-99');
});
Also in $.post
,
$.post( "php/processa-busca-cliente-atendimento.php", { id: <?php echo $user_id; ?>, nome: nome })
.done(function( data ) {
$("#resultado-busca").html(data);
$('.cpf').mask('999.999.999-99');
});
Updated, then try DOMSubtreeModified like,
$(function(){
$(document).bind('DOMSubtreeModified', function () {
if ($('.cpf').length) {
$('.cpf').mask('999.999.999-99');
}
});
});