KZ: How could it be the second that is chal? The first goy already own the chometz, so the second goy’s sale can’t be chal.
And what if Reuven sold his chometz via Rav Shimon first and Rav Levi second. But Rav Levi completed his sale to a goy before Rav Shimon did.
And I never heard anyone davka selling chometz through two or three different rav’s.