How to add promotional items directly to the cart?

Question

css

Good day, how to fix the problem, ordinary products from the main page, when you click on the buy button using AJAX, are added to the cart and the number of products and information about it increases at the top, but when I click to buy a product with a promotion (old, new price) , then first there is a transition to a separate product news, but I don’t need this, how to fix it, please tell me