I firmly disagree that this is a feature request, as in prior versions of Minecraft the music would pause when the game itself was paused.
Still affecting 1.21.8.
The thing is Jonathan, the download is a .zip file, not a .jar file, so the only way to install the snapshot is to copy and replace the files from the download into the minecraft.jar.
Dunno why it’s marked as resolved when it’s still occurring in 1.21.7.