The Third Man (1949)

1989 Criterion LaserDisc [CC1105L]: The sync issues and missing lines on the StudioCanal DVD and blu-rays originate here (or more probably the 1985 Criterion LaserDisc). More pressingly, all the fidelity issues (a massive lower midrange boost at 500 Hz and very little high-frequency detail - an overall dark and murky sound signature) are present here too. There is a fine layer of noise over everything that isn't on the Pioneer LaserDisc, but I believe this is just the analogue nature of the track. I hypothesise that the film's soundtrack underwent some sort of 'sweetening' in the '80s, as some higher profile films unfortunately had, and that mastering has been used for most releases since. 

1996 Pioneer LaserDisc [PILF-2291]: Like the Criterion LaserDisc, with the same sync issues/missing lines, though with less noise and slightly more detail.

1999 Criterion DVD: A different transfer. The sync issues are gone, although about 30 seconds are missing from the chase at the end (see black segment in below spectrals). There's still certainly some noise reduction, but there's significantly more detail too and that horrid echoey quality is gone. 

2006 Optimum DVD: Like the Pioneer LaserDisc (though missing the 30 seconds at the end). 

2007 Criterion DVD: Like the first Criterion DVD but with additional noise reduction - more muffled. 

2008 Criterion Blu-ray: A similar level of NR as the 2007 Criterion DVD. There is audible clipping during the opening music and on a couple short segments later in the film. 

2010 StudioCanal Blu-ray: Like the Pioneer LaserDisc, but further processed into fake stereo, with sound shifting violently between channels by the second. Horrible.

2015 StudioCanal Blu-ray: Additional noise reduction compared to the Pioneer LaserDisc. This sounds very poor. 

Sync issues and missing lines:
• 00:10:28: Mr. Hardtmuth should be asking, "Would you mind filling this in?" - his first 3 words are missing.
• 00:27:16: The sound of the drawer on the right opening now occurs twice (it's been looped). The sound is clearly wildly out of sync in the original mix, but this attempt to fix it is just... inept.
• 00:48:52: A second of dialogue from the film being played in the theatre has been looped. A German word spoken by the actress now repeats.
• 00:49:10: The taxi driver's line in German is completely out of sync with the actor, to the point where the viewer will now probably assume that he was originally dubbed. It's in perfect sync in every other version of the film.
• 00:56:47: Paine should be saying, "Very good, sir." The 'very' is missing.
• Most critically, about 2 minutes of footage in the chase sequence at the end is completely out of sync with the picture. Like, six or seven seconds out of sync, as if it's been assembled by someone without reference to any existing version of the film. The sound in this segment was cut, moved, and looped at various points in what was evidently a half-assed attempt to achieve a slipshod sync of sound and picture. Some of the shouting from the German police is also missing.

Obviously, the specifics of these errors would be lost to anyone watching the StudioCanal discs in real time. And the errors noted above are completely audible to anyone actively paying attention -- they are sounds that exist in the immediate foreground of the film's soundscape.

The only other track I'm still a little curious about is the one on the Japanese IVC LaserDisc, as IVC  sometimes used different source elements for their transfers.

Edit: Video comparison added, which I've made with the aim of drawing more attention to just how bad the StudioCanal track sounds. (My post for this film has gotten slightly more attention than others on this site, probably because the sync errors outlined above are objective and easy to understand... but I still maintain that the poor fidelity is the greater issue.) Note how the scrubbing away of low-frequency noise has inadvertently obliterated ambient sound too (distant cars, the movement of clothes as people talk, etc.) and note the absence of any real bass.

12/6/2023: Added the Criterion and Pioneer LaserDiscs