Shortcode [sale_products] lists regular price items

I have a page in my store for sale products, using the shortcode [sale_products per_page=”12″], but it fetches products that aren’t on sale. I can’t find a pattern to the products it’s listing, and on top of that the products are dead links. Any ideas? Thanks in advance.

http://reveljewelrydesign.com/sale/

http://wordpress.org/extend/plugins/woocommerce/