Quantity update is not updating the price on combination product on shopping cart page

[Jolsvi]

Hi,

I have been trying to solve this issue and searching through prestashop forum but haven't found any luck yet. Please anyone if you can suggest any solution.

So, I set the product catalog with the combination feature. Here are the rules:

- when you purchase 1 item, there is $0 decreased impact on price

- when you purchase 2 items, there is $1 decreased impact on price

- when you purchase 3 items, there is $2 decreased impact on price, .... etc.

 

The product page (front) is showing correctly when we update the quantity. But on the shopping cart (front), the "unit price" is not updated when we click + or - button. The total price is updated (but its not in the correct amount), its just showing the default calculation by multiply quantity with unit price.

Here I attached some images as an example. The result that  I'm trying to achieve on this example is I can add more quantity in shopping cart to quantity 3, unit price = $36, total price = $108