This video shows Best Actress winner Emma Stone backstage after the 89th annual Academy Awards, talking to the press. In her comments, she mentions how much they all would have loved for La La Land to win the Oscar for Best Picture, but how excited they are for Moonlight (which Stone says she thinks is one of the best films of all time).
She also made a point of saying, "I also was holding my Best Actress in a Leading Role card that entire time. So whatever story—I don't mean to start stuff—but whatever story that was, I had that card. So I'm not sure what happened."
Emma Stone might have been trying to imply that Warren Beatty and Faye Dunaway couldn't have had the wrong card, because she had it herself.
The thing is, there are actually two copies of each card, according to the LA Times. In a 2016 story, the paper explained:
In an undisclosed location, the partners tabulate votes and stuff two sets of winning envelopes, partly as another security measure and also to aid the show's flow. Stationed with their signature briefcases on opposite sides of the stage, either [PricewaterhouseCoopers partners, Brian] Cullinan or [Martha] Ruiz can dispense envelopes to presenters. At the end of the evening, each accountant will have given out about half of the envelopes.
And the third set? "There is no third 'set' sitting somewhere that has the winning cards in the winning envelopes,' Cullinan said. However, the remaining, unstuffed envelopes and nominee cards are shipped to a second secret location, just in case some disaster prevents access to the completed sets. After the ceremony, unused cards and envelopes are destroyed by an industrial document-destruction company.
In response to the Best Picture mix-up, Mahershala Ali said,
La La Land has done so well and has resonated with so many people, especially in this time when people need a sense of buoyancy in their life and need some hope and light. So that film has really impacted people, sort of in a very different way than Moonlight. When their name was read, I wasn't surprised. I was really happy for them. It's a group of some extraordinary people in front of the camera and behind the camera… And then when I did see security or people coming out onstage and their moment was being disrupted in some way, I got really worried. And then when Jordan Horowitz said, "Moonlight, you gus have won," it just threw me a bit. It threw me more than a bit. I just didn't want to go up there and take anything from somebody, you know? And that's very hard to feel joy in a moment like that, because somebody else… just, in front of them. But I feel very fortunate for all of us to have walked away with the Best Picture award. It's pretty remarkable.