Taking coal out of third hotbar slot, while in furnace interface, gives an XP orb.

Taking coal item out of third hotbar slot, while in furnace interface, gives an XP orb. Not sure if it's just coal, or if all items work, but it works with any furnace, and only works with the third hotbar slot. It's when you pick the item up with the cursor. It seems to be infinitely repeatable. Huge infinite XP exploit.

Update: This was marked as resolved, but it was happening to me in 1.18.30. It's still in the game. Am I confused about what resolved means?