I can reproduce this every time just by spending more that 10k in a shop. On the 10,000th scrap purchase it sill spit that stack out every time for me. In my case my shop has 4 vending machines and if I sell 5k worth of fuel in one and 6k worth of fuel in another one it sill spit out the 6k purchase because it put me over 10k. If you need me to show you just let me know and ill be happy to help,