User blog comment:Seieireppa/God Eater:Universitas, chapter 52: Au Bord de la Contre-Attaque/@comment-1419424-20150820155334/@comment-1419424-20150820185930

I figured this issue would come up eventually.

It doesn't affect the current Feldman's powers for two reasons. One of those is a spoiler, but the other is that, as with Ken's time leaping, changing events in the past doesn't alter future events; rather, it creates a branching timeline where events unfold differently. Remember back when Ken's power was revealed, and in the comments of that article I made the metaphor about the 100 bikers? It works like that.

The only thing is that, due to what'll be going down in the next few chapters, even that doesn't exactly apply. As for why, you'll have to wait and find out ;)

And as for Sigma, well... the implications of his absence have already been explicitly revealed. I won't say where, but it should be fairly obvious.

EDIT:  I suppose actually that it would affect the current Feldman's powers... but not at ALL in the way you'd expect. Just stay tuned for future chapters :3