HTML Comment <!-- <style> --> produces empty result

I have the following simplified PHP code, the HTML is coming from an untrusted source, and needs to be purified. This is a minimal example which reproduces the problem, my real HTMLPurifier config is a lot more complex.

$config = HTMLPurifier_Config::createDefault();
$config->set('Core.Encoding', 'UTF-8');
$config->set('HTML.Doctype', 'HTML 4.01 Transitional');
$config->set('Filter.ExtractStyleBlocks', true);

$purifier = new HTMLPurifier($config);

$dirtyHtml = <<<EOF
<!-- <style> -->
<style>
    div {font-size: 12px;}
</style>

<div>
    some text
</div>
EOF;

var_dump($purifier->purify($dirtyHtml));

The output is an empty string.

If I remove the "Filter.ExtractStyleBlocks" line, I get the correct output:

<div>
    some text
</div>

If I remove the HTML Comment from the $dirtyHtml, it also works fine. The problem seems to be this HTML comment in combination with the Filter.ExtractStyleBlocks.

As a quick workaround I remove all occurrences of <!-- <style> --> from the $dirtyHtml before purifying it, but it's just a workaround for now, until HTMLPurifier is fixed.

Start by running the minimal PHP reproduction using HTMLPurifier_Config, Filter.ExtractStyleBlocks, and HTMLPurifier::purify() to confirm the empty result. Trace the interaction between the HTML comment and style-block extraction, then verify that the sanitized output retains the div text and handles the comment without the workaround.