While you inside Pale Garden biome, then exit the world, Menu music will become silent until you restart the game or open the world then exit on other biomes.

Steps to reproduce:

1. Open Minecraft, make sure the menu music plays
2. Enter any world, go to Pale Garden biome then exit
3. Observe

Expected results:
Menu music plays as expected.

Observed results:
Menu music become silent.

Note:
this also affects Credits music, opening the credits screen from Settings > General > Credits while inside Pale Garden biome doesn't play C418 - Alpha soundtrack.