Quote Originally Posted by RyuDragnier View Post
Because Graha's time travel does not run on the same rules as normal time travel. Normal time travel sends you back on a linear time scale. Graha's also mixed space into the mix. Instead of just going back in time on the Source, which would have been a case of "can't change the past," he crossed space as well as time onto the First, a place where he doesn't/shouldn't exist. This breaks outside of the normal rules of time travel, which allowed him to change how things occurred. We could get into the nitty gritty about how that works (let's not for our own sakes) considering the Sundering first needed to take place, but it's going to be quite a few paradoxes.
Graha's time travel IS normal time travel, as Elidibus ghost warns us, if we go back in time and change anything, then the present we come back to will not be the same one we left from, and that we should be careful about that. He thinks this won't be a problem because we will be so Aetherically thin that we won't be able to have an affect on the past, but once we are there Emet-Selch and Hythlodeus change us into a form that CAN have an affect on the past, thus now causing a paradox.

Graha only ended up on the First because at the time of his jump into the past, the First and the Source had already been merged together due to the U8C. Graha's jump to the past is 300 years into the future after Stormblood. When he went back in time, he went to a pre-merged world and it landed him 100 years in the past (from Stormblood) on the First.