Index: wp-includes/comment-functions.php
===================================================================
--- wp-includes/comment-functions.php	(revision 34248)
+++ wp-includes/comment-functions.php	(working copy)
@@ -1669,7 +1669,7 @@
 	 * `wp_notify_postauthor()` checks if notifying the author of their own comment.
 	 * By default, it won't, but filters can override this.
 	 */
-	if ( get_option( 'comments_notify' ) && $comment->comment_approved ) {
+	if ( '1' == $comment->comment_approved && get_option( 'comments_notify' ) ) {
 		wp_notify_postauthor( $comment_ID );
 	}
 }