I have just found that by only adding the_content() to a template doesn't show the copy from the page you are on, but it get's it from nowhere (or somewhere else). Normally it would be empty, but in the situation I just experienced I had some boxes above the content area feeding titles and links from sub page – my copy ended up showing the text from the last box.
So instead of this:
<?php the_content(); ?>
Use this:
<?php if ( have_posts() ) while ( have_posts() ) : the_post(); ?>
<?php the_content(); ?>
<?php endwhile; ?>
