I have a multilingual shop her: http://youandyou.dk/temp/
Related & Cross-sells is not working in WooCommerce when WooCommerce Multilingual plugin is activated. So, when I edit a product in the admin and I want add related products in the Linked Products tab, it cannot find any products. When I disable the WooCommerce Multilingual, it can find related products.
I have tried to deactivate other plugins, but only get this problem when WooCommerce Multilingual is activated.