Mods that change world height break "DEEP_UNDERGROUND" tag?

[BronsonCarder]

So, I've been testing out my songpack and... it keeps playing calm4. I know, sounds like a ARG thing, but, it's supposed to only play deep underground in the overworld.
I am using Terralith + Tectonic. Tectonic changes the world height to 640, maybe that's part of the issue?

This is the songpack.
https://www.curseforge.com/minecraft/texture-packs/extra-tracks-history-restored

[BronsonCarder]

Another mod compatibility note:
It seems like Dynamic FPS, which should lower the music volume when Minecraft is unfocused, isn't working properly? I can still hear the music when the Dynamic FPS multiplier is set to 0%, though the volume is lower than it is in-game...