Cart rules

[Franzeweb]

Hi, I'm using prestashop 1.5.2.

I create a new cart rule (voucher) with the following action:

- discount of 50% on the cheapest product.

Using this voucher I observed the following behavior:

If I insert in cart two product one of 100€ and one of 80€ the total cart became 140€ (100 + 0.5 * 80 ) ,CORRECT

but if I insert only one product of 100€ the total price became 50€. WRONG

Is this behavior correct? The cheapest can be calculated even if there is only a product in the cart?

Please could someone help me to solve the problem?

I like to offer a discount of 50 % on the cheapest product in the cart only in case of total quantity higher than one.