Woocommerce 2.4.6 – Variable product issue

I still have the famous variable product issue, i tried all the fixing that i found here but nothing.

Basically, with the older version of woocommerce, I inserted all the variable product on my ecommerce and all worked fine. Every product (t-shirts) had different sizes and every product size could be or not in stock. After the update all sizes are out of stock.

This is an exemple of a product that is in stock only in the Medium size but seems out of stock in every size.

http://www.mamuk.it/shop/blasoni-black-green/

Can you help me? The theme is update to the latest version and support woocommerce 2.4.4

thank you

https://wordpress.org/plugins/woocommerce/