If they had just screened a bunch of voice actors and chosen the same one no one would care (legally or otherwise).
(and given the timeline ScarJo laid out in her Twitter feed, I'd be inclined to vote to convict at the present moment)
The discovery process may help figuring the intent - especially any internal communication before and after the two(!) failed attempts to get her sign-off, as well as any notes shared with the people responsible for casting.
I think a lot of people are wondering about a situation (which clearly doesn’t apply here) in which someone was falsely accused of impersonation based on an accidental similarity. I have more sympathy for that.
But that’s giving OpenAI far more than just the benefit of the doubt: there is no doubt in this case.