The left is what the original looks like right as the cutscene switches to that scene. It only looks like that for a fraction of a second and then it renders correctly and looks like the image on the right. In the video, the guy mentions how he added a hard drive overclocking feature to make that pop in not happen or at the very least, significantly reduce it.
But yeah out of context that thumbnail is confusing.
'If You Give A Dev A Tricked Out Xbox, They’ll Patch Halo 2' - Hackaday article (hackaday.com) angielski