I have noticed the same thing logged in Wordfence when using it in conjunction with the "Rename wp-login.php" plugin.
Anyone who attempts to access wp-login.php gets redirected to the invalid /-/-/-/-/-/-/-/ URL.
Based on this thread in the support forum for Rename wp-login.php I believe this can be stopped by blocking access to wp-login.php through .htaccess but I haven't tried it myself yet.