Double use of ID "comment-xx"

Hello,
Just wanted to hear your opinion,
I had a validation issue because of the comment.module using :
$output .= "<a id=\"comment-$comment->cid\"></a>\n"; (on line 1573)
and the advf-forum-post.tpl.php using :
<div id="comment-<?php print $comment->cid; ?>" class="forum-post <?php print $classes; ?> clear-block"> (on line 34)
so I have changed this line to :
<div class="comment-<?php print $comment->cid; ?> forum-post <?php print $classes; ?> clear-block">

What do you think ?
Will this cause any other issues ?