It looks like someone on the twitter thread checked and the checksums are wrong. Im not sure why these packets aren't discarded by your computer.
edit: apparently osx doesnt drop these packets according to the twitter thread.
edit: apparently osx doesnt drop these packets according to the twitter thread.
Generally - both the tcp checksum and the 802.11/Ethernet CRC isn't all that strong, so it's entirely within the realm of possibility of having bitflip patterns that fool both.