The bug

When in one certain Nether biome, an ambient sound from a different biome can play. Here are some examples with attached clips:

• When the player is in a Warped Forest biome, you can constantly hear the Nether Wastes Ambience track playing, and the slightly quieter Warped Forest Ambience is hard to hear over it. (mis_amb1.mp4)
• When the player is in a Warped Forest biome, sometimes the sound Crimson Forest Addition 1 can play. (mis_amb2.mp4)
• Likely more that I haven't noticed

Looking at the Minecraft Wiki Ambience page https://minecraft.gamepedia.com/Ambience#Nether_ambience, I don't think any biome ambience should play in two different biomes, with some exceptions for the Basalt Deltas.