Lightbox not working on certain links

When opening the thumbnail link on posts (example: http://paperburners.com/huf-plantlife-socks/ ) lightbox doesn’t work. It does work when I manually insert an image link in the page, so it seems to be specific for those links. They are retreived within genesis hooks with the: wp_get_attachment_url( get_post_thumbnail_id($post->ID) )
line and link directly to an image, so Lightbox should work. What can be the issue and how can I fix this?

https://wordpress.org/plugins/simple-lightbox/