I don't think she did this "on purpose", but from how quick her decision came she doesn't seem that resolute about AKB48. That's been obvious for a while. Skipping TOKYO DOME of all things was a big clue. And really, if that's how she or anyone else feels, then they should go. There's plenty of girls out there that being in AKB is their whole dream. Not that I want to see her gone so quickly, but yeah..
I hate to see her bow out on such a low note, though. Japan's entertainment industry doesn't like shit like this so it will stain her name a bit in some circles. However, given her talent and interest, she's going into an industry that may not care as much about silly tabloid "omg you like boiz" scandals. I mean, without the idol mark it means pretty much nothing. I think she understands she's gotten what she needed from AKB48. She's getting out there and getting work, it'll get to a point (if it hadn't already) that AKB was more in the way than anything else. This isn't a situation like Sashihara where it's worth her effort to fight and stay in AKB48 post-scandal, or for management to fight to keep her. I don't mean that as an insult towards Yuka, that's just... how it is. I think she knows that, too.
I hope she finds the success she wants. She's definitely got the talent, way too much talent to be only an AKB theater girl.