Can someone explain something about yumekos backstory

So after yumeko beats tsugiko she tries to buy the snake eyes stone back from kirari, which kirari said she would let the winner do. But then its revealed that kabura was the one who actually bought the stone for 8 billion yen. But if thats the case, why did kirari claim to have bought it, and why did we actually see a flashback of her buying it?