'GoogleSignIn is marked as internal and should not be accessed from app' for new Google Play Services implementation

Question

I'm implementing the new 'simpler' Google Play Services implementation (no GoogleApiClient management) and am getting redlined with the error 'GoogleSignIn is marked as internal and should not be accessed from app. This API had been flagged with a restriction that has not been met.' Despite the error flag my game app still compiles and runs, and has been able to access Leaderboards and Achievements. I'd like to get rid of this flag and to know if it's more than something that should just be hidden from lint, as I don't see how I'd access GoogleSignIn outside of my app.

Games.getLeaderboardsClient(this, GoogleSignIn.getLastSignedInAccount(this))
            .getLeaderboardIntent(leaderboard_id)
            .addOnSuccessListener(new OnSuccessListener<Intent>() {
                @Override
                public void onSuccess(Intent intent) {
                    startActivityForResult(intent, RC_LEADERBOARD_UI);
                }
            });

UPDATE 4/2/18: I've been finding more Google Play Services code error flags after the 12.0.1 update which fixed GoogleSignIn. As previously with GoogleSignIn, they don't affect the compile or run, but are still irritating.

Answer 1

Known issue - Read #4 https://developers.google.com/android/guides/releases#march_20_2018_-_version_1200 Google says it can be safely ignored.