WooCommerce – doesn’t show product when using woocommerce.php [closed]

I found the answer – might be obscure, but still might help someone:

Apparently the custom navigation template messed up / overwrote the “$posts” array, so I just saved the original, and restored it after including the navigation:

<?php
$saved_posts = $posts;
get_template_part('tpl-nav');
$posts = $saved_posts;
?>

Just added to to the top of the woocommerce.php template and it fixed the problem.