Joe Alwyn received additional production credit for Taylor Swift’s “august” after Folklore won Album of the Year.
The song was produced by Swift and Jack Antonoff, while Joe Alwyn was later recognized as a co-producer. Alwyn worked on Folklore under the pseudonym William Bowery, a credit that became widely discussed in connection with the album.
The distinction between the original liner-note credits and later recognition matters. Wikipedia notes that Swift and Antonoff are credited as producers in the Folklore liner notes, while the Recording Academy recognized Alwyn as a co-producer after the album won at the 63rd Annual Grammy Awards.
This is why answers naming Antonoff can seem partly correct: he was an original credited producer and co-writer. The question asks specifically who received the additional recognition, which was Alwyn.