To me that voice never sounded like her. Even when I try to listen as if it is really her talking. The voice in the movie 'Her' was very distinct. Not this one though.
What about the voice of actress who actually did lend her voice for Sky? Can she claim that this is her voice?
The angle of why they would want to protect the voice actor's privacy? My guess is that their fear is people becoming attached to the voice in a sort of parasocial relationship, then seeking out the original voice actor to try and turn that parasocial relationship into something more.
If I were a voice actor, I wouldn't risk sharing my name because 95% of VAs and creators in general would hate me. It's like declaring "I'm using AI to enhance my art" on Twitter, but worse.
Did you read the part where they approached her to "license" the voice up until days before release? Plausible deniability would be a lot more believable if that wouldn't have been the case.
What about the voice of actress who actually did lend her voice for Sky? Can she claim that this is her voice?