Coupon will be multiplied with amout of items in cart

hi!

the coupon i've created for only one product will be multiplied with the item amout of the whole cart. this was not the idea of the purpose of the coupon.
i set the coupon discount type to price:

I found this code that does the multiplication:

else if ($coupon->type == 'price') {
$result->amount = min($applicable_total, $applicable_qty * $coupon->value);
}

why is $applicable_qty the amout of items of the cart?

what do i have to do that this is working properly?

thanks in advance!