Reply To: free items not updated in cart

[info53]

WooCommerce ver 3.2.5
WooCommerce Extended Coupon Features PRO ver. 2.5.4

Discount type: sconto fisso sul prodotto
Product: #73
Minimum quantity of matching products: 2
Maximum quantity of matching products: 20
Free products: #73
Auto coupon, Apply silently

the first time I add the product to the cart from the product page, the plugin works (es. I buy 10 item, in my cart are shown 5 free items) but when I go in the cart page and modify the amount of product to buy, the quantity of the free product does not change