Analyze and Fix Code Issues

At ITW Performance Polymers, a batch-allocation script picks which raw-material lots to draw from (oldest-expiry first) to cover a production order, then updates the inventory. It's been in production for a few weeks and a plant supervisor has flagged that the numbers "look off."

def allocate_batches(order_qty, batches):
    # batches: list of dicts like {"lot_id": "L102", "qty": 500, "expires": "2026-10-01"}
    # Allocates batches FIFO (oldest expiry first) to cover order_qty (kg).
    # Returns list of (lot_id, qty_used) and updates batches in place.
    batches.sort(key=lambda b: b["expires"])
    allocations = []
    remaining = order_qty

    for batch in batches:
        if remaining <= 0:
            break
        use = min(batch["qty"], remaining)
        batch["qty"] -= use
        remaining -= use
        allocations.append((batch["lot_id"], use))

    for batch in batches:
        if batch["qty"] == 0:
            batches.remove(batch)

    print(f"Allocated {order_qty - remaining} kg, {remaining} kg short")
    return allocations

Can you analyze this piece of code and identify any potential issues?