Error with product related coupon at the cart

Hello guys,

We created a coupon for a single product that has 100% discount. The problem is when the customer uses this coupon with this product at the cart and another one, because the system apply the 100% to all the products at the cart.

This configuration is standard, or is it a bug at Marketpress?

If is standard, why we can choose for a single product when create a new coupon? Is this correct?

The solution was to replace the lines`
if ( $coupon = $this->coupon_value($this->get_coupon_code(), $total) )
$total = $coupon['new_total'];`
by

foreach ($cart as $product_id => $variations) {
    foreach ($variations as $data) {
        $price = $this->coupon_value_product($coupon_code, $data['price'] * $data['quantity'], $product_id);
        $totals[] = $price;
        $product_count++;
    }
}
$total = array_sum($totals);