redirect_uri_mismatch when OAuth2 account linking from Google Home Simulator

I am developing an account linking integration for an "Actions on Google" integration with API.AI for use with Google Home. When I test this agent in the simulator (https://developers.google.com/actions/tools/web-simulator)

As expected, this is my response:

{
    "response": "It looks like your conference manager account is not linked yet. You can link conference manager to your Google Account from the Google Home app.",
    "audioResponse": "//NExAARC..."content_copy,
    "debugInfo": {
        "sharedDebugInfo": [
            {
                "name": "Account Linking Url",
                "debugInfo": "https://assistant.google.com/services/auth/handoffs/auth/start?provider={project-id}_dev&return_url=https://www.google.com/"
            }
        ]
    }
}

However, when I follow the

res.debugInfo.sharedDebugInfo[0].debugInfo

link, I get the standard redirect_uri_mismatch error page, with the details:

The redirect URI in the request, https://oauth-redirect.googleusercontent.com/r/my-project-id, does not match the ones authorized for the OAuth client. Visit https://console.developers.google.com/apis/credentials/oauthclient/my-client-id?project=my-client-id to update the authorized redirect URIs.

It's of course not possible to add the googleusercontent domain to the redirects, and this isn't the redirect I have specified in my API.AI Actions on Google intergration.

On the API.AI side my Auth Url is the standard Google one: https://accounts.google.com/o/oauth2/v2/auth

and my token URL is: https://myendpoint.com/google-home-token-endpoint with the Scopes filled in as calendar

On the google developer console, I have the token URL set to the same as in API.AI, and the project id/client id the same as reference in the requests.

Is this a known issue? Additional debugging efforts I can try?

Solution

See Leon's comment on my original question.

It is not currently possible to do account linking with Actions for APIs you do not own.