Playing in my personal realm and i smelted a ton of stuff in my furnace that has hoppers removing the items to store XP. Flipped a lever to allow me to pull out items manually for XP but removing one item brought me from 6 levels to 14 (which is a lot for 1 pull), but then it went back to normal. I had no mending items in my inventory. I smelted nearly a full chest of stone, food, and various ores, so I should have gotten a ton more than that. As it is working now this is useless for enchanting or mending.