And lots of people that are in the middle class now and vote for Bolsonaro came from families that lived in poverty when Lula came to power the first time. The only article that I could find in English describing the paradox is https://www.populismstudies.org/dr-nogueira-trumps-influence-is-shaping-brazils-election-making-it-a-very-important-and-dangerous-one-2/ :

Dr. Nogueira argues that Lulism remains anchored in the Northeast and among lower-income voters, but has become increasingly defensive. She suggests that “Lulism has perhaps become a victim of its own success,” as social mobility has altered popular aspirations and Lula’s political appeal has become more closely associated with defending past achievements than promising transformative change.

In Portuguese there are many more articles, but general gist is that people that climbed the social ladder from poverty are now more focused on protecting and furthering their new status than in helping the people that are still stuck in poverty. And it's not even a Brazilian phenomena, there have been similar voter behaviours in Portugal, Turkey and India for example.

the working class of the richer parts are highly elitist and love acting like petit bourgoisie, there was extreme xenophobia against internal migrants of the poorer parts (northeast) into the richer parts (southeast, specially São Paulo), and more recently against also fellow LATAM migrants and the few African migrants from former Portuguse colonies. They have risen up from porverty into "middle class" during PT's (Lula's party) previous rule, and now are highly reactionary and elitist, the intelectual elite in brazil has generally being right wing for centruys, and being so prominent in the southeast region they have spread their ideas most strongly there and in also have often become part of the economical elite (the bourgoisie) themselves