claims from id_token are not passed to k8s cluster

[SnehaMore20]

I have deployed kube-oidc-proxy and authenticating using Keycloak into our K8s cluster. But I have observed that kube-oidc-proxy takes claims only from refresh_token and not from id_token.
e.g
refresh_token given below

{
  "aud": "https://keycloak.example.com/auth/realms/test",
  "azp": "k8s",
  "exp": 1611054882,
  "iat": 1611053082,
  "iss": "https://keycloak.example.com/auth/realms/test",
  "jti": "*",
  "scope": "openid profile email",
  "session_state": "*",
  "sub": "*",
  "typ": "Refresh"
}

id_token given below

{
  "acr": "1",
  "aud": "k8s",
  "auth_time": 0,
  "azp": "k8s",
  "email": "[email protected]",
  "email_verified": false,
  "exp": 1611052668,
  "family_name": "test",
  "given_name": "",
  "groups": [
    "/test1",
    "/test2"
  ],
  "iat": 1611052368,
  "iss": "https://keycloak.example.com/auth/realms/test",
  "jti": "*",
  "name": "test",
  "preferred_username": "test",
  "session_state": "*",
  "sub": "*",
  "typ": "ID"
}

when i pass "--oidc-username-claim=sub" to kube-oidc-proxy , it works and authenticates correctly.
but when i pass "--oidc-username-claim=email" to kube-oidc-proxy, logs throws error:

1 handlers.go:169] unauthenticated user request 10.12.12.192:51378

and kubectl throws error:

error: You must be logged in to the server (the server has asked for the client to provide credentials)

So basically I am not able to use claims from id_token.
Is there any way I can user claims from id_token?