Defender URL masking redirect issue

Defender masking url option is not working properly for some default login url. When trying to access login page with a default url like 'wp-login.php', it redirects to the proper url set in redirect field. But if accessing through 'wp-admin', it still show the login form.

Basically: - shows login page - works as expected - works as expected

I'm also getting the following errors in log files:
PHP Warning: Invalid argument supplied for foreach() in /wp-content/plugins/wp-defender/app/module/ip-lockout/component/login-protection-api.php on line 411
and this one
5:09 pm
[23-Apr-2018 10:32:29 UTC] PHP Warning: count(): Parameter must be an array or an object that implements Countable in /wp-content/plugins/wp-defender/app/module/ip-lockout/controller/main.php on line 505