Error message when updating users in WP admin

SU version 4.9.2

When updating user profiles as an admin user get this:
Notice: Undefined index: update in /xxxxxx/wp-content/plugins/shortcodes-ultimate/inc/core/tools.php on line 694

line 694

if ( $_GET[‘update’] === ‘del’ || $_GET[‘update’] === ‘add’ || $_GET[‘updated’] === ‘1’ ) delete_transient( ‘su/users_cache’ );

Only seems to occur when as an admin user edit and save other user profile

https://ww.wp.xz.cn/plugins/shortcodes-ultimate/