The artifacts are actually there on every frame in which the lightning rifle is being fired. I just posted the most obvious ones. But you're right, it doesn't ruin the experience and it's much easier to live with than the revisionist BD colours.
Out of curiousity though, would it be possible to replace these shots with scenes from the HDTV version? I know it's open-matte but it could be cropped to 2.35:1 to blend with the BD video.