2014 theme full width feature image

Hey, I have been trying to get a custom post template added as an exception in the template-tags.php file of the WP 2014 theme. The code looks like this:

function twentyfourteen_post_thumbnail() {
	if ( post_password_required() || is_attachment() || ! has_post_thumbnail() ) {
		return;
	}

	if ( is_singular() ) :
	?>

	<div class="post-thumbnail">
	<?php
		if ( ( ! is_active_sidebar( 'sidebar-2' ) || is_page_template( 'page-templates/full-width.php' ) || is_post_template( 'single-presentation.php' ) ) ) {
			the_post_thumbnail( 'twentyfourteen-full-width' );
		} else {
			the_post_thumbnail();
		}
	?>

The issue is, the post template is not registering as an exception to the thumbnail rule. This means all posts under the template are by default 2014 thumbnails and not full width. Any help would be really appreciated.

Cheers.

https://www.ads-software.com/plugins/custom-post-template/