There is another one at 21 seconds. Basically every view has one object. Yeah the object is probably a white sphere. Having trouble downloading a 4k copy to check (if you can point to a 4k copy please link). What troubles me is even if he was running a 1/500 shutter speed the UFO should be blurred (longer) that it is. For a 25 frame per second frame rate in late afternoon I doubt he would be running a higher shutter speed.