I'm prepared to believe it as the malignant takeover on the right was well on its way, Fox and RW radio was booming, etc. And PBS has been increasingly underfunded and taking big-donor money in return for covering specific topics and angles for some years now. But could you be thinking of generally after Gwen Ifill's death in Nov 2016? I started noticing unmistakable NewsHour bias some time after Woodruff was anchoring alone. But, again, I haven't made a study and that's just when I was forced to realize that RW media corruption has taken that over also.
Btw, on looking up Hunter-Gault's departure, I noticed that UGA's first black sorority just had its 50th anniversary, 56 years after she was one of the first two black students.