Does the gform_notification_email filter still work?

I think the filter is boken in some way, because when I change it to this, it stills fails. I.e. it still reverts to admin email field and not bob@example.com.

add_filter( 'gform_notification_email_3', 'route_notification', 10, 2 );
function route_notification($email_to, $entry) {
   //global $post;
   //$email_to = get_the_author_email();
   $email_to = 'bob@example.com';
   return $email_to;
}

OK, one major difference, is that I originally had my code in single.php, I've now moved it to functions.php. Things have improved slightly, now the following code works:

add_filter( 'gform_notification_email_3', 'route_notification', 10, 2 );
function route_notification($email_to, $entry) {
	global $post;
	//$email_to = get_the_author_email();
	$email_to = 'bob@example.com';
	return $email_to;
}

Where as the following code fails completely:

add_filter( 'gform_notification_email_3', 'route_notification', 10, 2 );
function route_notification($email_to, $entry) {
	global $post;
	$email_to = get_the_author_email();
	//$email_to = 'bob@example.com';
	return $email_to;
}

I don't think get_the_author_email() is working for some reason. What's the best way to see if it's being set properly? I'm not quite sure how to echo out variables from filters...

That worked! Is get_the_author_email defunct now?