According to the US CDC website(
http://www.cdc.gov/ncbddd/hemochromatosis/) "Hemochromatosis occurs when the body absorbs too much iron from foods (and other sources such as vitamins containing iron). This disease causes extra iron to gradually build up in the body’s tissues and organs, a term called iron overload. If this iron buildup is untreated, it can, over many years, damage the body’s organs." sounds pretty nasty!!
Isn't lack of clotting more to do with clotting factors (or their lack) than the metal bound to your blood cells. I know in humans different types of haemophilia is generally caused by lackof different clotting factors eg Haemophilia A lacks clotting Factor VIII, Haemophilia B lacks clotting Factor IX, and Haemophilia C has a lack of the clotting Factor XI. The most common is haemophilia A.
Abalone (which also use haemocyanin) are haemophiliacs, cephs do not appear to be, otherwise we'd never get any surviving who had lost arms.
BTW cephs do have blood cells they're called amoebocytes (Witmer & Martin, 1973).
J
Witmer, A. Martin, A. W. 1973. The fine structure of the branchial heart appendage of the cephalopod
Octopus dofleini martini. Cell and Tissue Research.
136(4): 545-568.