The model itself is over the 20k limit, and thus violates the Terms of service distributed by the developers, But given the hundreds of people and worlds that use models over that limit i don't see and excessive amount of bans happening, but we'll see.
You Need to install the SDK like in the websites tutorial into unity after you open my package, then go into the READ ME!! Folder and follow the instructions.
JuicyJames, you just need to remove the jaw flap bone on the avatars descriptor and that should fix it, if you have any other issues you can message me in the VRCMods discord.