Keycloak with Discourse

So I’m missing some configuration, because if I enable the OAuth2 with Keycloak, authenticate myself on Keycloak and an another tab try to access my Discourse intance I’m redirect to Discourse login page and need to click on “Log In” (blue button) to Discourse verify with Keycloak that I’m already authenticated.
I really don’t want that anonymous users be able to read my Discourse instance.