Case Activity form tpl produces bad HTML

When creating/editing an activity in CiviCase, the generated HTML has weird table errors.

Here's how to see the error:
http://hrmaster.demo.civicrm.org/civicrm/case/activity?reset=1&cid=258&caseid=20&action=update&id=1042

Do a "view source" on Firefox, and it will highlight in red a few places of the HTML.

For example:

<table class="form-layout">
<table class="form-layout-compressed">
<tbody>
<tr id="with-clients" class="crm-case-activity-form-block-client_name">

or another, near the Attachments:

</table>
</td>
</tr>
<tr class="crm-case-activity-form-block-attachment">
<td colspan="2"> <div class="crm-accordion-wrapper collapsed">
<div class="crm-accordion-header">Attachment(s)

the errors cascades to a few other places.

It's not really critical since I guess no one noticed it in 4.5, but while working on a 4.3 -> 4.5 upgrades (I know, I make no sense LTS-ly), I ran into problems because it broke my custom Javascript on complicated forms.