The graphql api documentation is saying:
LineItem.discountedTotalSet
The total line price after discounts are applied, in shop and presentment currencies.
(https://shopify.dev/api/admin-graphql/2022-07/objects/LineItem#field-lineitem-discountedtotalset)
But when we fetch line items data for discountedTotalSet we get value without applied discount 
For example an order is for one product that is cost 1 USD and to this order we apply 50% discount
Via graphql api we will get:
Order.totalPriceSet = 0,5 USD
LineItem.discountedTotalSet = 1 USD (but should be 0,5 USD)
Is that a bug or discountedTotalSet behavior/return value was changed?