Now, here's what I'm thinking which might explain the difference in patterns throughout the years. The original effect was probably shot on film and telecinéd to videotape, and then filmed off of a tv for the original effect. When they went in to recomposite everything in 97, they skipped the filmed off a tv element and went straight for the original film. The video effect was then added using computers.

Perhaps one should check the moment when the hologram distorts when it's turned on and off and see if the distortion is exactly the same between pre and post 97. It looks like the original effect was created by simply mucking with the tv signal. If the whole tv image was recreated in 97, they would have had to recreate that with cgi.