In my Prestashop 1.7.5 store I have some products with Shipping Fees, they all have the same additional fee (12.00).
I noticed that for each product with Shipping Fees that is added to the cart, instead of using a fixed shipping of 12.00, its being multiplied by all the products with that additional fee:
This is not the intended result, it should be 12.00 for all the products.
How can I solve this issue? Is is there any Prestashop setting that I'm missing?
This is working as it should. Shipping fee is added for each product. It's not aggregated. You can't do what you want with PrestaShop. Probably there are some modules to do it.
Other thing that you could try is to create a new carrier and set higher fees, only for these products.