Swift, Antonoff and St. Vincent, real name Annie Clark, weren't actively involved in the creation of songs for Sour, and were instead credited after Rodrigo and producer Daniel Nigro interpolated one of their songs.
According to Billboard, a statement from the Recording Academy read: "During the submission process, the Academy received credits from the label for the track "deja vu". Last week, we received the correct credits from the label that recognize Annie Clark, Jack Antonoff and Taylor Swift as songwriters of an interpolation on the track, "deja vu". In keeping with current Grammy guidelines, as songwriters of an interpolated track, Clark, Antonoff and Swift are not nominees in the album of the year category for Sour. Antonoff and Swift are nominated in the category for Swift’s album, evermore.
Like the statement said, Swift and Antonoff are up for Album of the Year for Swift's evermore, and Antonoff is also nominated for Producer of the Year, Non-Classical. St. Vincent's latest album Daddy's Home also has a Grammy nomination for Best Alternative Music Album.