Found it — thanks for the clear repro. Kumbi/Subi/any throwing-star (and gun bullet) stack is *supposed* to survive at 0 so a shop can recharge it, and firing your last one was doing that correctly. The bug was one step later: InventorySystem.removeItem() was wiping EVERY empty slot in the whole bag as a side effect, not just the one it was asked to touch — so the very next unrelated bag action (drinking a potion, a quest turn-in, selling something else, feeding a pet) deleted your empty star stack before you could reach a shop to recharge it. Fixed removeItem() to only delete slots it actually drained itself, and closed a matching hole in the shop's Sell row (an empty stack was pricing at the full stack value and could hide the Recharge button). Pushed to the dev branch just now — not yet confirmed in a live playtest, so leaving this in_progress rather than fixed. Please re-test: fire a star stack down to 0 and confirm it still shows in your bag and can be recharged at a shop.

Update: the fix is now LIVE on play.mapleverse.online (deployed just now, on top of the earlier dev-branch push — it'll also reach the Verse8 preview automatically). I also restored the Kumbi Throwing-Star that was lost to this bug directly onto Saint's character (your bag had room, so it landed back in your Use tab rather than storage). Please go ahead and re-test when you get a chance: fire a star stack down to 0 and confirm it survives and can be recharged at a shop.