ISA Browns are sexlinks, not autosexing.
Sexlinks are a one-time cross, while autosexing will breed true in the next generation (like Cream Legbars and Bielefelders)
But I agree that mixing up gender on color-sexable chicks is something no-one expects. Maybe someone was careless that day. Or maybe he is a Starlight Green Egger, and they messed up on some other method of sexing.
