Musannaf Ibn Abi Shayba 35:200

Abu al-Ahwas narrated to us, from Tariq, from Sa'id ibn al-Musayyib, that he disliked [the exchange of] fresh dates for dried dates, measure for measure. He said, "The fresh date is swollen, and the dried date is shrunken." And it was mentioned that Abu Hanifa and Abu Yusuf said, "There is no harm in it."