From the Washington Post:

It’s not clear how many New Yorkers have been affected, but advocates said the issue appeared to be widespread in Brooklyn. “I have heard from dozens of voters individually today, all concentrated in Brooklyn, that they have received return ballot envelopes that are not in their name,” Ali Najmi, a New York elections lawyer, told The Post.

Michael Ryan, executive director of the New York City Board of Elections, said that he learned of the error on Saturday, Gothamist reported. Ryan blamed a vendor with a contract to print and mail absentee ballots for voters in Queens and Brooklyn.

Meanwhile, early in-person voting starts Oct. 24, 2020 in New York.