Incorrect price with product promotions in Paytrail

Problem/Motivation

When adding a coupon code and discounting the total price, the price looks fine in the cart. When you are going to pay via Paytrail, it adds a extra discount (percentage discount) to the already discounted price.

original price 75 -> discount of 5 -> 70 -> Going to pay via Paytrail -> Adds another (not wanted) discount of some percentage -> 64