OIDC provider scope template

Vault
1

In doc:
https://developer.hashicorp.com/vault/docs/concepts/oidc-provider#scopes

I see that I can use for oidc provider scope template variable $MOUNT_ACCESSOR:

{
    "username": {{identity.entity.aliases.$MOUNT_ACCESSOR.name}}
}

But when I generate id_token from endpoint:
My JWT token has empty attribute:

{
  "username": ""
}

When I use template without variable:

{
  # // I replaced "username": {{identity.entity.aliases.$MOUNT_ACCESSOR.name}} with plain text of auth accessor name
  "username": {{identity.entity.aliases.auth_kubernetes_663278c3.id}}
}

Id token has correct username

{
 "username": "96739f72-3d56-84ab-a00c-49b19eb73486"
}

It looks like variable MOUNT_ACCESSOR doesnt work or maybe this is a issue in documentation