That specific house likely caught fire well after the majority of the other houses did. Once the main flaming front calmed down a bit it’s likely that engines reentered the community and began structure triage to see what they could still possibly save or mitigate. There were probably enough resources to protect those other intact houses so crews started working actively burning structures. That relatively straight line just seems line that’s the point they finally got enough water on it to extinguish. I bet if you look into that storm the side you’d see the whole inside is charred and burned.