While it doesn't excuse her batshittery, I remember Lindsay dubbing Allison's singing in a review (I think it was "The Little Mermaid"...I have an image of Allison with her dyed red hair & construction paper purple seashells taped to a flesh toned camisole), I think with Elissa's singing. No one told her it was going to happen, she just assumed they asked her, they would use her voice. As a 19 to early 20-something year old, I can see how that would really hurt. Not that Allison has ever considered herself a singer on any level (I think), but still---that's a shitty move.
Years later, after she left CA, she talked about it. And she sang "This Is The Moment" from "Jekyll & Hyde".
https://www.youtube.com/watch?v=cJ5iKRpE41E
She isn't a singer by any means, and that's a tough song to sing. But she was sufficient. I mean, for an online review show.
As I said, it doesn't excuse her behavior, but I just remember it and I can see how that may have made a chip on her shoulder about CA from the beginning. Performers have always been screwed over (hell, ghost singing cost Audrey Hepburn an Oscar nomination), but you get pissed, then learn from it, then move on & don't make the same mistake again. I also remember hearing somewhere (I can't remember where, I'm sorry...I spent a good amount of time racking my brain but I just can't) that Allison was asexual...which might help explain her long term, long distance relationship with Phelous. I'm not saying that sex has to have a huge portion of a relationship (long distance or otherwise), there are plenty of other ways to have a normal, healthy functional relationship....but....yeah. Do with that what you will. As I said, I just remember hearing it.