Undefined property: WP_User::$user_level

Using version 4.1.3
Turned on debug so that I could check a theme I am working on and noticed persistent Undefined property: WP_User::$user_level at 1ine 1355

To get the plugin to stop with the debug notices I inserted a isset test on $current_user->user_level

Not sure what the implications are. (new to php and wp)

I’m running in maintenance mode which could be the problem.

function yoast_ga_do_tracking() {
$current_user = wp_get_current_user();

if (0 == $current_user->ID)
return true;
// stop debug notices fix
if (!isset($current_user->user_level)) {
return true;
}