A bug in the coupon code discount

As soon as a customer enters a coupon code in the shopping basket, the discount is given to him from the maximum price in the option of bu,ndle (set) discount. I would have used the option of  bulk discount, would have given the coupon code from the final price after discount,
For example, a shirt costs $30, if he loads 5 into a cart, $150 comes out.
I gave him a coupon code for a 10% discount, the discount should be given from the final price ($100) and he gives the customer a discount from the price of $150, in other options it was not like this