I've have this two issues by now:
1- when we buy an item, cart is shown with the item for seconds and then its auto refresh to 0 (but the product is inside the cart)
When you buy from this link http://www.pizzeriadolomiti.es/producto/4-formaggi the basket change inmediatelly to zero (but the pizza is inside) You can see 2 screenshot attached (18.00.02 and 18.00.04), shooter at the same second, before and after change the number of items into the basket.
2- Sometimes, when you buy two or more products, one extra cent is added in the Total.
When you buy pizza with options, an extra cent is added, Why? (see attach 17.34.57)