Duplicate ID’s in comment form

Element ID’s are meant to be unique on a HTML page. Here is a little bit of code where I've found two comment-form ID's.

<section id="comment-form">
      <h2 class="title">Add new comment</h2>
      <form class="comment-form" action="/d7/comment/reply/1" method="post" id="comment-form" accept-charset="UTF-8"><div><div id="edit-author--2" class="form-item form-type-item">
  <label for="edit-author--2">Your name </label>