The Shining (1980)

This movie has enough obsessive fans to nitpick its home video releases, so my contribution will be small.

This video compares the 5.1 remix to the original mono mix. As the author observes, there are some clear 'errors' in the 5.1, mainly with the Penderecki pieces at the end of the film. ...But in the grand scheme of things these changes are minor compared to those of other films (see most entries on this site); it's really just the popularity of The Shining that draws more attention to them.

The main issue I have with the 5.1 is the differences in fidelity between the score (mixed from the original stems) and everything else (dialogue, onscreen sound effects, etc.). They just don't mesh well, and the mono sounds a lot less like someone is playing live orchestral music behind you while you try and watch the movie. There are some moments of unfortunate hiss reduction in the 5.1 too (also noted in the video), but there also moments where dialogue sounds more detailed than in the mono.

I haven't looked for other minute differences, but here's one I caught by chance while skipping through: at 1:16:38 (UHD timecode), the "We're sorry..." phone voice that Scatman Crothers hears is (intentionally) slowed and pitched down in the original mix but lacking that effect in the 5.1.

Of the two home video releases with the mono mix that I've heard, the 1999 4:3 Warner DVD sounds better; the 1991 Warner LaserDisc is noticeably more muffled and missing high-frequency detail. The difference is comparable to the LD/early DVD of A Clockwork Orange, but less extreme than the LD/early DVD of Full Metal Jacket.

It's worth pointing out that synchronising the US/long cut to the European/short cut is very straightforward and can be done just by overlapping adjacent segments with an audio editor, which suggests that the European cut never had a unique sound mix—just one adapted from the US cut with truncations.