Possible <Glossary>/<Subtitle> bug?

I'm experiencing some odd behaviour
with the XHTML Stylesheets when processing Glossarys.

For example:

<glossary>

  <title>A Glossary</title>

  <subtitle>subby gloss</subtitle>

...

</glossary>

outputs:

<div>

  <h2 xmlns="http://www.w3.org/1999/xhtml"
class="title"><a ...></a>A Glossary</h2>

</div>

<div>

  <h2 xmlns="http://www.w3.org/1999/xhtml"
class="subtitle">subby gloss</h2>

</div>

Glossary.xml (from the latest full
release) provides:

<!-- ********************************************************************

     $Id: glossary.xsl,v 1.15 2003/02/28
16:44:35 bobstayton Exp $

     ********************************************************************

...

<xsl:template match="glossary/title"
mode="component.title.mode">

  <h2 xmlns="http://www.w3.org/1999/xhtml">

    <xsl:apply-templates/>

  </h2>

</xsl:template>

<xsl:template match="glossary/subtitle"
mode="component.title.mode">

  <h3 xmlns="http://www.w3.org/1999/xhtml">

    <i><xsl:apply-templates/></i>

  </h3>

</xsl:template>

I can see that match="glossary/title"
is working as expected to produce my <h2>s but for some reason match="glossary/subtitle"
isn't getting called to produce my <h3>s - I get another <h2>...

Am I understanding the XSL correctly
or is there actually something wrong? There's nothing outstanding on the
Sourceforge bug tracker...

TIA

Mart