maybe next update
The current update has not fixed the music issue. Very rarely the music works properly but the music played suddenly stops after a minute like if someone has done the “/music stop” command. So It's either incorrect biome music, or correct biome music with sudden stops.
The music is still bugged in the Copper Age update.
I tried this on the current beta and preview, and the music was playing as normal in their correct biomes.
Yes. This is still an issue in the latest none beta version of the game.
I can confirm that it's finally fixed in the recent mounts of mayhem update. It surprises me that hardly anyone noticed this bug. Ecko, if you are reading this bug report, hello!