Unable to Logout of Identity Provider Auth0 Office Addin

I am developing a Microsoft Office Add-in that is using Auth0 to manage user logins. I am using Google SSO (identity provider) in Auth0.

I was able to add the login capability to my app by following this example on github: https://github.com/OfficeDev/Office-Add-in-Auth0

However I am now trying to add functionality to log the user out. I am calling the logout endpoint through a cors proxy (i host my own proxy that i use) as so:

https://cors-anywhere.herokuapp.com/https://{MY_AUTH0_DOMAIN}.auth0.com/v2/logout?
        federated&
        client_id={MY_CLIENT_ID}&
        returnTo={MY_RETURN_TO_URL}

The call will return a 200, but when I go to the login screen and sign in with google I am not presented with the screen to select my gmail. I am just logged into the app with the gmail i used the first time.

The only thing that logs the user out of their gmail (identify provider) is by manually "clearing the web cache" in the add-in.

I have tried following these instructions: https://auth0.com/docs/logout/log-users-out-of-idps I setup the proper clientId for google, so that i am no longer using the dev keys.

Has anyone successfully added logout functionality for an identify provider with auth0 in an office add-in?