That's odd, Anitta has actually always been very vocal and critical of Bolsonaro on Twitter from what I've seen.
There's even an interview from 2019 where she explicitly says that she doesn't support him at all: https://vogue.globo.com/beleza/gente/noticia/2019/02/em-entrevista-internacional-anitta-fala-sobre-o-presidente-eleito-jair-bolsonaro-e-sobre-seu-posicionamento-politico.html