When trading with a villager that has a discount, sometimes when you trade, it will it not give you items and even sometimes it will not give you items and steal your emeralds.

When trading with a villager that has a discount, sometimes when you trade, it will it not give you items and even sometimes it will not give you items and steal your emeralds. Sometimes it will give you some items but not all of them, when this happens the emeralds get stolen like if you received all of your items.