This is a fork of issue  http://crbug.com/661230 . Fieldset doesn't work properly with multiple <legend> tags. Example: http://codepen.io/anon/pen/eBpaOX

Per https://www.w3.org/TR/xhtml1/dtds.html#a_dtd_XHTML-1.0-Strict there is 1:1 mapping between fieldset and legend. That's why I think the correct behavior should be displaying only the first <legend> and ignoring all others <legend>s.