Villager still holding up trade item after the hotbar slot has been depleted

When an item (or a stack) is being held up by the player, the villager who will trade for that item holds the corresponding trade item up. If the player starts trading with the villager, and uses up all the items that were in the active hotbar slot, the villager will still be holding the trade item, despite the fact that the player now has an empty hand. This persists until the player changes the hotbar slot.