It was in Uncanny X-Force. He basically just got sick of all the death and hate and wanted more for himself. So he was offered a better life by Archangel in the 616 to essentially become a thug for him, and Bobby accepted it (along with AoA Blob). You got the gist that he had just hit rock bottom so badly that he stopped caring about anybody. I was cautious at first because I really liked him in the AoA, but he ended up being an awesome bad guy. I hope he's able to make a return at some point, or that they use 616 Bobby like that more.
And Corp, the Death Seed was also an Uncanny X-Force creation. Technically, I suppose it was a retcon, but being that we never saw exactly how the tech changed Apocalypse's Horsemen of Death, it still fit without problem. I don't recall the details of it, but I know it has something to do with a Celestial.