If I use the /playsound command to play a default sound with the new names, like entity.pig.ambient, it works fine. But if I try to play a sound added by a resource pack, I get no sound, even though it says it's been played successfully.

To make sure, in my resource pack's assets/minecraft folder, I have a sounds.json file defining the following event:

{
  "magikos.wand": {
    "category":"ambient",
    "sounds": ["magikos/wand"]
  }
}

In its assets/minecraft/sounds folder, I have a directory called magikos and in there, an OGG file called wand.ogg. I reload the resource pack in-game with F3+T, and when I try to use /playsound magikos.wand @p, I get the successful message but no sound.

Again, it works perfectly fine with the built-in sounds like entity.pig.ambient, and all my sound options are turned up to 100% and working fine naturally. It's just resource pack sounds that don't work.

EDIT Attached the actual resource pack, which is just for testing so far. And the exact command I'm trying to use (again, testing by entering it directly into the chat) is simply /playsound magikos.wand @p, but it has the same non-effect if I specify the rest of the optional parameters as well.