Your evil, lost twin.

Yeah, doesn't surprise me. This would be the first time that Ive noticed a goof in the excellent trailers that Bethesda releases for TES and Fallout though. It was bound to happen sometime, and this is really on the small end of computer animation goofs in big blockbuster stuff.

Bugs don't work that way.

You guys forgetting that a world stimulation technology exist in fallout, and this scene could be just an simulated restoration of that event.

I think it's just an editing mistake. Maybe someone forgot to erase Sole Survivor from that segment so for a brief moment, lasting only a second, he appeared in the Pre-War bits where he logically shouldn't have been. I will, however, entertain the notion that this means there's a moment in the game when we can actually (sort of) go back to the Great War and observe it. Maybe to find out what happened to our spouse and child when we went under?