Hi Clayton,
You might have some other plugin (or in your own functions.php) that is calling add_filter on the ‘the_content_more_link”. Try changing the priority in the add_filter call to be a larger number (say 99 instead of 16) and see if this solves the problem.
Also, make sure you’re using my version of the plugin. Look at 474 of wp-show-posts.php and make sure it looks like this:
<?php
$content_more_link = apply_filters('wpsp_content_more_link', false, $settings );
the_content($content_more_link);
?>
Jon