Mix and Match Discount

HI Everyone,

One of our clients want to apply a mix and match discount. They want the first 2 items to have a discount and when they add a third item to the transaction, it should have the original price.

For some reason, when we select 2 items it applies the discounted price but as soon as the third item is added, all the items change to the original price.

Please advice on how to fix the issue.

Thanks