It happens all the time. Obviously, they switched to a new system. The Historical Testing of Futures Trading Systems is not an Accurate Model. Most of the historical results I've seen make major assumptions that are simply not acceptable. There is simply no way to know exactly what price you would have actually received during a real trade.
Futures prices change constantly.
Even then, the data has to be adjusted because of contract expirations. There are also other considerations such as lack of liquidity, and bad order fills that cannot be represented in historical models. When you see impressive historical results for Futures Trading Systems remember that they are just an estimation. In real-live trading during the historical period the system may or may not have actually been profitable. Futures Trading Systems are Really not Very Accurate at Timing the Market.