Error in Cart Rules and Catalog Price Rules behavior - Prestashop 1.7.6.5

[Alberto Castaño]

I recently configured a 20% discount voucher, using Cart Rules (Catalog -> Discounts -> Cart Rules). In the Voucher's configuration I chose to exclude the products which already had a discount (see figure #1).

Parallel to this, I created a 5% discount to one of the brands on the e-commerce, using Catalog Price Rules (Catalog -> Discounts -> Catalog Price Rules). 

However, when the cart had two items, one with a discount and one without, the voucher was applied to all of the cart. Even to the product with previous discount. 

• If I put into my cart only products with no discount and add the voucher, the cart will automatically add the 20% discount to the complete order (just as I configured it). See figures #2 (product without discount) and #3 (cart with voucher successfully applied)
• If I put into my cart only products with discount and add the voucher, the system will not let me continue due to my previous configuration. Excluding from the voucher's discount those products that already had a discount. See figures #4 (product with configured discount) and #5 (cart with voucher successfully rejected).
• However, if I put into my cart at least two products (one with a discount and another without one) and add the voucher, the system will apply the voucher's discount to all of the products, even if I chose to exclude every product that already had a discount. See figures #6 (cart with both products, voucher applied to every product - BUG) and #7 (excel table showing results and the difference between what I expected and what really happened) 

Is there a way to fix this error?

 

FIGURE #1

 

FIGURE #2

FIGURE #3

 

FIGURE #4

FIGURE #5

FIGURE #6

FIGURE #7

 

Edited November 23, 2020 by Alberto Castaño (see edit history)