CompMovieGuy said:
Are you positive about this? I was under the impression that the print used was an original early 80s 70mm workprint and not a restrike of an older print revived. From what I remember, the workprints were owned by theaters and in the 90s they started to show them again, select nights, WB caught wind of this and made the D cut of the movie

But why would a workprint be blown up to 70mm in the first place? That's what makes no sense to me - it makes more sense if a few theaters wanted to do 70mm screenings, WB ordered new prints struck for said screenings, and someone got the film canisters mixed up and blew up an old workprint to 70mm by mistake, and the mistake wasn't noticed until the screenings had already happened. I could very easily be wrong, though, that's all just conjecture on my part - I just don't understand why anyone would blow up a workprint to 70mm intentionally.

Is it possible that, since the effects sequences were done in 70mm, it was cheaper to blow the rest of the film up to 70mm than to make a reduction print of the effects down to 35mm, and that's why the screening print of the workprint was 70mm? That's the only reasoning I can think of.

And you could be right that the 70mm scanner used caused the error - I just think it makes more sense to me that it was an error in making the original blow-up/dupe print/whatever.