In truth, I can foresee no other alternatives. Either the timeline changes so little it conforms without trouble, or it splits. Else how else could the past that was, the past that becomes, the future that was, and the future that becomes all exist, when each is necessary for the scenario to occur?

[Venat has experience with this all, of course, but worth mentioning also is that she immediately identified a time-traveler absent any knowledge that such an act was possible. When she says that nothing felt impossible to her any more, she is not speaking metaphorically nor hyperbolically.]

I am aware of numerous smaller-scale ones that occurred for unclear reasons over the course of my time as Hydaelyn. Strangely, they all seemed diverge primarily on the identity of the Warrior of Light.