And she also had trouble going SSJ2 a second time, so there's a precedent for her having trouble. That's the whole reason she went USSJ. She didn't learn naturally like Cabba did.
She could have just been drained. She went USSJ, which Goku said was tiring her out, to SSJ2 for the second time, and she stayed that form during the whole fight with Berserk Kale vs. Goku.
Yep, and because she is different we can't just assume that she achieved Super Saiyan 2 in a fashion that is exactly similar to the level of mastery that Gohan, Goku, Vegeta, etc has achieved.
It may not be something they explain to us right away, but I suspect she maybe has a ways to go where stamina control is concerned while using those transformations. Even if they don't explain it, it will be demonstrated more than likely in her at some point being overpowered by an opponent she can't beat. It won't necessarily mean she would've won if she had super saiyan 2 fully mastered, but perhaps she would perform better if she did.
As we've seen with both the new saiyans from universe 6 so far, they master transformations, or at least getting control of them fairly instinctively, but they, thus far, appear to be wreak havoc on their stamina reserves. There is a reason they've needed to do so much resting up during this tournament thus far, whereas more powerful saiyans like goku, vegeta, gohan and the rest haven't stopped to take anywhere near the length of rest and recovery period that Kale and Caulifla have had to. So when people think that these two characters are broken in an unchecked fashion, they truly aren't. They've been limited as compared to more practiced Super Saiyans even if they may possess more raw potential compared to someone like Cabba.
And it's been said already by Goku that he knows they'll become even more powerful, and that's likely to happen in this very tournament. We just don't know what form that will take. I just believe the status quo thus far regarding their seeming lack of stamina management after using Super Saiyan transformations may ultimately be their core weakness right now.
And it's beginning to be quite clear that Cabba is being saved for something, or is a lot more powerful than he has been given credit for thus far. Perhaps he'll be the first to challenge Frost for his treachery with Freeza.
