in design / block /home page / featured product
the option Hide add to cart button: for product2 and small multicolumns don´t work for me.
for small multicolumns add to cart work and no duplicate order in cart
for product2 add to cart appear in frontend and if you click add to cart button he put product X2 in the cart.
for product2 product duplicate in cart x2 = number of product categories , if you dont use multicolumns no problem ,no duplicate
if you use multicolumns x2 or x3 the product is duplicate in cart x2 or x3