*** Bug 473 has been marked as a duplicate of this bug. ***

Possible Solution by modifying Chef Class
Original
	public void cook(int time)
	{
		if(remainingTime == 0 && isAvailable == true)
		{
			Output.output(this.order, time);
			isAvailable = true;
			this.processedCustomerOrder.add(this.order.getCustomer().getTokenNumber());
			return;
		}
		else
		{
			remainingTime -= 1;
		}
	}

Changed to:

	public void cook(int time)
	{
		if(remainingTime == 0 && isAvailable == false)
		{
			Output.output(this.order, time);
			isAvailable = true;
			this.processedCustomerOrder.add(this.order.getCustomer().getTokenNumber());
			return;
		}
		else
		{
			remainingTime -= 1;
		}
	}