Variety magazine said the LA's Finest star had raised concerns with producers and was leaving after just one series.
Sag-Aftra, which represents actors and performers, is looking into the case.
NBC, which makes the show, said it was "committed to ensuring a respectful workplace for all employees".
Last week, the former judge's husband, ex-basketball player Dwyane Wade, said she had been "fired" and he was "still waiting on a good answer" to explain why.