Just did my 500 Shotgun kills on the quest, thinking I was finally done grinding that crap since the heroic infamy part was checked off many matches before already. Only to find out that the Rank part gets unchecked when the rank is reset in between! What the hell. I was under the assumption that once a quest part is checked off, it stays checked off. I have no intention of farming even more Gambit for the rank, even less since the rank progress is so much slower than the normal PvP ranks. tl;dr: reseting Infamy rank resets the quest step too. be aware of this BS.