Even this is not an error and just a notice I thought I'd pass this along:
Notice: Undefined index: notification_to in /usr/share/wordpress/wp-content/plugins/gravityforms/notification.php on line 75
I'm getting this when I have a notification with 50+ routing options under the admin notifications when I go to edit that listing. But all the routes appear to be there and adding/saving additional routes does not seem to cause them to get lost.