Mario Mash-Up music not playing in the nether

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Is this still an issue in the latest version? If yes, can you please add it to the affected versions (or mention it if you are not the reporter)?

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According to MCPE-177292, yes

Is this still an issue in 1.21.2?

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This is still a current issue

Resolving temporarily as Awaiting Response. Does this issue occur in newly created worlds?
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Attempted this issue some time ago (on Nintendo Switch), in Release 1.21.2, for me, I Cannot reproduce the issue with the newly added resource pack thus newly created worlds.

As I cannot find the mash-up pack's sound definitions (sound_definitions.json) in human readable format, nor the music in the resource pack that was usable on media player, in official ways, I had to do these in game on Nintendo Switch.
To reproduce the issue, I activated the resource pack from Super Mario Mash-up Pack, set the music volume to 100%, and since I don't want to spend too much time listening to music surfing the Nether, I then used commands "/playsound music.game.soulsand_valley", "/playsound music.game.crimson_forest", "/playsound music.game.nether_wastes" and "/playsound music.game.warped_forest", with "/stopsound @a" ("/stopsound @s" can be used if you only want to stop sounds for yourself) after each to skip the music early, and repeating each until I could hear any soundtracks that could be available without the resource pack on. Which I had never heard once.

The result might be inconsistent so if you find any way to successfully reproduce the issue or as the developer of the mash-up pack who find the issue in the it's sound definitions, please let me know.

Edit: the way I had reproduced in 1.21.2 cannot be reproduced in 1.21.20 because /stopsound defaults not muting music in the latest version and would result in music played from commands overlapping. I might find another way to reproduce myself sometime later, but still developers have to check the mash-up pack's sound definitions and mark it fixed if there was no music that could be played without the mash-up pack on.

If anyone could prove the issue still persists in the latest version, please comment which version and have the video evidence attached.