I have found an issue in this question: How to get list of values in GROUP_BY clause?

Check this out. I enter the following piece of HTML:

<code><pre>hello</pre></code>

It is rendered as such:

hello

When I check the rendered HTML in my browser, what I get is this:

<p><code></code></p>
<pre><code>hello</code></pre>

So some extra <code/> element and paragraph are rendered.