I recall that she was resistant, or else shouldn't the game have ended earlier? You probably mean this right?
As I claimed I fervently think she is presumably BSing to gather precious time, she is probably immune to at least one lynch hoping for us to lynch her so she can rub it on our face and call us out, out of our misery, so that we probably don't lynch her again once proven wrong.
She is patently not behaving like a Survivor, and she voting herself might otherwise be a way to simply avoid being lynched in this phase by playing a WIFOM strategy.
The first scenario looks more feasible to me. But the second too, expecially if she truly has a resist that isn't connected to this phase specifically.
She is either an horrible survivor or a scum and so if she is scum I obviously doubt that she would reveal to be immune to the D1 lynch if that was not convenient to her, so perhaps she did so because she would like to avoid consuming her first lynch resist so that she could gain time and it might be consumed later on. Unless she prefers consuming it now / is truly immune so that if she is lynched she can rub it on our face and claim ha-ah you messed up, you better trust me from now on.
I don't quite buy that she probably didn't lie about something here, finding it overall unlikely... unless it can work off; but nevertheless the overall structural pattern fits properly to me.
As I explained a Buffer + Survivor never profusely convinced me in the first place, for all the reasons I deeply elencated. But she could play the intangibility card to mess with our minds. But I'm no pushover.