Storywriter Felice Kuan said Max's power has atrophied due to not using it for a long time. So, I think what happened is Max didn't use her power at all until the Asteroid was about to impact the Earth & in desperation she used her photo she took earlier alongside Moses and Safi to try to Photo Focus and change something in the past to hopefully prevent the Asteroid's destruction (and probably to save Safi too, if Safi had originally died). Since Max's power had grown weak, however, she didn't fully change reality with it. Instead, the "Autopilot Max" who we play in the game has access to both the altered reality where Safi is alive & the original reality where Safi's dead. Max's photo focus wasn't strong enough anymore to perform "garbage collection" and destroy the original timeline. Eventually, our Max will find Daniel whose power can help stop the Asteroid.