Board Thread:Manga/@comment-27321453-20190908104148/@comment-37493549-20190919075755

Eren can't see the entire future, he just gets random glimpses of it. Also the future that he chooses (that is, his own actions that he chooses) is always the one that was going to happen anyway. That's just how it works. If seeing the future is the thing that caused him to act that way, that's also fine. He didn't change the future by doing that because that was always going to be the future, he was always going to do that action. Doesn't matter if the motivation for the action was seeing the future.

There's never any reason for these guys to change the future 'just because lets fuck the timeline', the choices that make the future happen as they saw it are ones they already had the motivations to make anyway. Grisha telling Zeke to stop Eren won't change anything, he was 'destined' to say that if you like just like the future he's trying to stop is 'destined' to happen.