Random 501 errors when refreshing token

Starting on Wednesday June 8th, we are getting randomly 501 errors when trying to refresh tokens:
```json
{"error": {"code": 501, "status": "UNIMPLEMENTED", "message": "Operation is not implemented, or supported, or enabled."}}
```

Here is the code that generates this error:

```php
$client = new \Google_Client();
$client->setApplicationName(config('google.APP_NAME'));
$client->setClientId(config('google.CLIENT_ID'));
$client->setClientSecret(config('google.CLIENT_SECRET'));
$client->setAccessType('offline');

$client->setAccessToken(TOKEN);

if ($client->isAccessTokenExpired()) {
\Log::debug("access_token expired");
$refresh_token = $client->getRefreshToken();
$new_access = $client->fetchAccessTokenWithRefreshToken($refresh_token);

// $new_access sometimes returns this error {"error": {"code": 501, "status": "UNIMPLEMENTED", "message": "Operation is not implemented, or supported, or enabled."}}
}
```

When we manually connect again the Google account (which generates and stores a new refresh token), the accounts refreshes correctly, and then after a few refresh fails again with a 501 error