Which period piece was it? I recall some controversy about something like that a while ago, but couldn't remember exactly what it was about.
I was more referring to the article written recently about how having all white casts in period pieces should be banned. You could be thinking of the film King Lear, Troy: Fall of a City, BBC's the story of Britain, or the 2016 Robin Hood series. There's been so much blackwashing of historicals that it's hard to keep track.