I put cold taiga, snowy forest, snowy coniferous foret, snowy dead forest...in both taiga and snow category for getting both sounds, but I only the snow sounds and not the taiga sounds. It's the same for snowy tundra I placed in both plains and snow category, I only get snow sounds. Snow sounds seem to override all other sounds, while it's not the case for all other sounds which can play in the same biome.

by Hypsellis (originally posted here: https://minecraft.curseforge.com/projects/ambientsounds?gameCategorySlug=mc-mods&projectID=254284#c31)