Okay there is queasy kitty as a minifigure but does uni kitty actually puke in the film like throwing up or tossing cookies is a side effect of sea sickness but since that there is no proof that uni kitty throws up
maybe it's her fault that she always holds in her vomit once it comes out of her stomach she maybe forces to swallow her vomit back in to her gut.
She may have emetphobia (the fear of vomiting) a condition that makes people have that fear to force their tossed cookies down into their stomachs or uni kitty is just a little sissy or possibly does not want the Lego water to get contaminated by her own vomit
WARNING: Contains mild spoilers
After the submarine sinks (since it is badly built it ends up flooding) and they float on the Double Decker Couch (they hide inside the cushions). Straight after she comes out, she's Queasy Kitty. In a matter of seconds, she's back to normal. I don't even recall her being Queasy Kitty on the pirate ship.
I didn't notice her puke. It's probably because she can hold it in, and control her 'positive thoughts'. I know that I never have positive thoughts when I'm about to puke.