And you know why, don’t you? The Apple Store illumination is LED and with the frequency recording set on that app, and such sensitivity (ISO), that flickering is also noticeable.Everything in that video is flickering including the background image.
But if you don’t find it useful you can freely ignore it. I’ve been testing PMW with that app for several years, and this year the flicker is different, with smaller black bars and faster flicker.