I had some bug in backend magento 2.2.3
Steps to reproduce
1.Create a discount rule based on attribute set which have configurable products
2. Save & Apply rule
3.Run command reindex to apply catalog price rules
4.Open Backend Magento 2 : Go to Customers -> All customers -> Choosen one customer
5. Click Manage Shoping Cart -> Selected product has discount rule -> Click " Add selections to my cart " .
Product has been added showing correct price with discount rule like in frontend. ( Discount 30% )
Backend :I tried to click " Update Items and Quantities" in backend, but product had price rule not updated price.
Price of product showing incorrect, but subtotal show correct price when product had discount rule.
I tried to reproduce in Magento 2.3. No error to show,price had discount rule showing correct , pls let's me some my mistake. Thanks!