You can solve it by commenting on line 458 of the index.template.php although I don't know if it is the right option, the line of code apparently affected is:
<a href="', $button['href'], '"', isset($button['target']) ? ' target="' . $button['target'] . '"' : '', '>', $button['title'], '</a>
I don't know what effects it will have on the rest of the site but I will try to prove if something fails and if it is necessary to adapt the line.