I’m with James. I would love to see your other videos. I’m not trying to dismiss anything out of hand but I got to go with what I know. I deal with digital video on a regular bases and have a good understanding of happens during the capture and reproduction process.
More than likely it is a digital video artifact. Today’s digital cameras are loaded with technology and software that try to interpolate the image and record to digital media. There is a long list of artifacts that can be produced by the process. This likely a compression artifact produced by the camera.