Ibuki has severe trust issues. The "creative differences" she was talking about were actually her band mates treating her like she was a pest that they needed to get rid of and when they weren't treating her like a pest they were treating her like she was a song making robot. Worst part about all of this was that they pretended to be her friend. One day Ibuki caught them bad mouthing her and calling her a "Hyper Active Freak". That day was the day she decided to quit the band. If they can't accept her for who she is, then she has no reason to stick around.