In playing the campaign (both classic and reforged) on the current live version of Warcraft III, the following bug occurs: when loading a saved file from within a campaign map, such as to reset to an earlier point in the same mission, the game music starts playing double. This can be mildly annoying if the music that plays ends up being the same track twice, as it is simply overlaid onto itself with slight delay, but it can also end up playing two different tracks at the same time, which makes for a terrible audio experience.
Deactivating music removes both instances of music, and re-enabling it brings both back.
The same(?) bug also appears in a second case: whenever an end of campaign FMV is playing, the regular game music is playing over it as well. Even without any saving or loading. This really hurts these pivotal story moments as it’s clearly not meant to be as such.
Game is played on MacOS, so it may be an issue exclusive to it.
As you said, it really ruins those story moments, especially the FMV scenes.