Wrong output html if table's caption contains headers

Hello, on this example HTMLPurifier 4.9.2 returns bad output html:

$text = '<table border="1" style="width:300px">
    <caption>
        <h2><strong>caption</strong></h2>
    </caption>
    <tbody>
        <tr>
            <td style="width:64px;text-align:right"><strong>Life:</strong></td>
            <td style="width:80px"><strong>063-560-10-10</strong></td>
        </tr>
        <tr>
            <td style="width:64px;text-align:right"><strong>Skype:</strong></td>
            <td style="width:80px"><strong>saleusa</strong></td>
        </tr>
        <tr>
            <td style="width:64px;text-align:right"><strong>Viber:</strong></td>
            <td style="width:80px"><strong>0973151111</strong></td>
        </tr>
        <tr>
            <td style="width:64px;text-align:right"><strong>e-mail:</strong></td>
            <td style="width:80px"><strong>info@saleusa.com</strong></td>
        </tr>
    </tbody>
</table>
';

$config = HTMLPurifier_Config::createDefault();
$p = new HTMLPurifier($config);
$html = $p->purify($text);

Output html is:

<h2><strong>caption</strong></h2>
    
    <strong>Life:</strong>
            <strong>063-560-10-10</strong>
        <strong>Skype:</strong>
            <strong>saleusa</strong>
        <strong>Viber:</strong>
            <strong>0973151111</strong>
        <strong>e-mail:</strong>
            <strong>info@saleusa.com</strong>

But if I remove h2 tag (change caption to <strong>caption</strong>) everything OK.
Is this a bug or may be I just not turn on some settings?

Start with HTMLPurifier_Config::createDefault() and HTMLPurifier::purify(), using the supplied table and caption markup as the reproduction. Compare the output when the caption contains an

with the output when it contains only , then add a regression check for the expected table structure. Done means the table and caption are preserved correctly in both cases.