This worked for us.

First, we need to get id_token from Keycloak along with access_tokenwhen getting token from keylcoak.

To get id_token from keycloak we need to set scope=openid for the keycloak token REST API.

Once we have the id_token during logout we called the Keycloak logout directly from browser as GET request in below format (not from backend application).

https://keycloaktest:8443/auth/realms/<realmName>/protocol/openid-connect/logout?id_token_hint=<idTokenValue>&post_logout_redirect_uri=<postRedeirectURL>