In my opinion, this isn’t exploiting a flaw. It’s simply smart betting based on predictable behavior in low-volatility markets, something BK8 should have considered when designing the game or hosting the game.
Do let me know if you need further explanation on this to clear things up.
In your side it’s truly a smart betting but on the casino side it’s a flaw since they design a game that shouldn’t be beat by a strategy. Most gambling games should rely on luck when winning while in your case it’s a calculated betting like card counting on blackjack that guarantees win.
Hence you will not grow your 120$ to 80K+ if your strategy is not a sure bet.
I think BK8 need to accept their mistake on their game design and pay you assuming they will not provide substantial evidence for their decision.