It's because Confetti cats breed differently.
They actually have 4 fours:
2 Confetti furs (shown and hidden)
2 non-Confetti furs
They ALWAYS have to be paired with another Confetti cat in order to have a CHANCE of passing their Confetti furs. Even when breeding a pair of Confettis, in my experience they only give their Confetti furs about 25% of the time.
If a pair choose to give their Confetti furs, they will each give one of their Confetti furs and one of their non-Confetti furs, and the OS will show the Confetti fur that is most dominant.
If they decide to not to give their Confetti furs or they are paired with a regular cat, they will only give one of their non-Confetti furs, and the OS does NOT hide any Confetti furs.
More Info:
https://kittycats.ws/forum/showthread.php?tid=22770
So, the Genesis fur is coming from your Confetti. You'll need to get it a Confetti partner if you want ANY chance of getting Confetti babies.