In retrospect, I overstated the case, when I indicated that the chunk in question has an effect on pages that don’t explicitly use it (sorry about that). However, adding comments to the offending chunk does in fact create significant problems for the site in IE7. Here is the code:
<h2>Links</h2>
<div id="links">
<!--This is a comment. -->
<p><a title="Test Link1" href="http://www.testlink1" target="two">Test Link1</a></p>
<p><a title="Test Link2" href="http://www.testlink2.com" target="two">Test Link 2</a></p>
<p><a title="Test Link3" href="http://www.testlink3.com" target="two">Test Link 3</a></p>
<!--This is a comment. -->
</div>
If I leave the comments in the code above, any page that calls the chunk will display very improperly in IE7 (namely, most of the page content will not even display). I have tried this numerous times, and reliably, I get the same troubling result. As soon as I remove the comments, the problem disappears. Can’t seem to get my head around it.