Doxia generates different XHTML for the same xdoc code

Consider the following xdoc code:

<section name="1">
<subsection name="s1">
<p>p1</p>
<ul>
<li>l1</li>
</ul>
</subsection>
<subsection name="s2">
<p>p2</p>
<ul>
<li>l1</li>
</ul>
</subsection>
</section>

This renders to the following XHTML code:

<a name="1"></a><div class="section"><h2>1</h2>
<a name="s1"></a><div class="section"><h3>s1</h3>
<p>p1</p>
<ul><li>l1</li></ul>
</div>
<a name="s2"></a><div class="section"><h3>s2</h3>
p2
<ul><li>l1</li></ul>
</div>
</div>

Please not the missing <p> </p> around 'p2'.