I thought I’d post the solution even though this is quite old. The problem is caused by the sidebar and footer being left out of the wrapper due to a misplace div. The culprit is in comments.php.
If you find
<!-- You can start editing here. -->
You will see
<?php if ($comments) : ?>
followed by
<div class="comments-template">
This means if the condition isn’t met, you’re going to be missing the opening div but you will still have a closing div at the end.
The solution is to simply take
<div class="comments-template">
and put it before
<?php if ($comments) : ?>
Tom Doidge