My Sections user page screws up my HTML5 template

Okay, there are two culprits at play here.

Here's the content area of my page.tpl.php:

<section id="content">
        <div class="wrapper">
            <section id="main">
                <?php print $messages ? $messages : ''; ?>
                <?php /* print $breadcrumb ? $breadcrumb : ''; */ ?>
                <?php print $title ? '<h1>'.$title.'</h1>' : ''; ?>
                <?php print $tabs ? $tabs : ''; ?>
                <?php print $help ? $help : ''; ?>
                <?php $thefront = node_load(11); ?>
                <?php if($is_front) {
                         print node_view($thefront);
                         } else { print $content; } ?>
                
                <?php if($support): ?>
                  <section id="support">
                    <?php print $support; ?>
                  </section>
                <?php endif; ?>
                
                
            </section> <!-- #main -->

            …

        </div> <!-- .wrapper -->
</section> <!-- #content -->

And here's the corresponding HTML of the My Sections page:

<section id="content">
	<div class="wrapper">
		<section id="main">
			<h1>My sections -- Fake teacher</h1>
			
			<ul class="tabs primary">
				<li ><a href="/users/fake-teacher"><span>View</span></a></li>
				<li ><a href="/user/3/edit"><span>Edit</span></a></li>
				<li class="active" ><a href="/user/3/sections" class="active"><span>My sections</span></a></li>
			</ul>
		</ul>
	</div>
	
	<div id="menu-access">
		<ul class="tabs secondary">
			<li><a href="/user/3/sections/444">District Administration</a></li>
			<li><a href="/user/3/sections/445">Hoxie High School</a></li>
			<li><a href="/user/3/sections/446">Hoxie Elementary</a></li>
		</ul>
		
		<div class="clear"></div>												
		
		<div id="menu-access-create">
			<div class="item-list">
				<h3>Create content</h3>
				
				<ul>
					<li class="first"><a href="/node/add/assignment?section=444">Create new Assignment</a></li>
					<li><a href="/node/add/event?section=444">Create new Calendar event</a></li>
					<li><a href="/node/add/gallery?section=444">Create new Gallery</a></li>
					<li><a href="/node/add/lesson-plan?section=444">Create new Lesson plan</a></li>
					<li><a href="/node/add/organization-info?section=444">Create new Organization info</a></li>
					<li><a href="/node/add/story?section=444">Create new News story</a></li>
					<li><a href="/node/add/support-request?section=444">Create new Support request</a></li>
					<li><a href="/node/add/teacher-info?section=444">Create new Teacher info</a></li>
					<li class="last"><a href="/node/add/teacher-resource?section=444">Create new Resource</a></li>
				</ul>
				
			</div>
		</div>
		
		<h2>District Administration</h2>
		
		<p>The table below shows the content assigned to this section. <em>You may not be able to edit all content.</em> Ask your site administrator if you have questions about this page.</p>
		
		<p>You may use the links to the right to create new content in this section.</p>
		
		<table class="sticky-enabled">
 			<tr>
 				<th>Title</th>
 				<th>Author</th>
 				<th>Type</th>
 				<th>Status</th>
 				<th>Operations</th>
 			</tr>
		</table>
</section> <!-- #main -->

It's hard to tell because it won't keep my effing indentation, but there are two problems with the rendered HTML. At the end of the second "paragraph" of code in the second snippet above, there's a spurious </ul></div>. This is the main problem that causes the HTML hierarchy to be so screwed up. Also, the <div id="menu-access"> is never closed properly.

I'm digging through the PHP now to see if I can come up with a patch.

That ul / div issue is coming from tabs primary -- e.g. the menu system -- not MNE.

I'm not much of a Drupal developer, so I suppose that's technically possible, but the only page on the whole complete site on which this problem manifests itself is the MNE page. On every other page, including several pages with both primary and secondary local tasks, Drupal plays nicely. So it has to be MNE's interaction with something, even if MNE isn't inserting the code itself.

The only thing that occurs to me is that "Section" is a special word in MNE, and I'm using <section> tags, so maybe MNE interacts with those poorly somehow? Seems far-fetched, but something's happening.