Defender – lots of messages to PHP error log


I’m running Defender Pro on my PHP 7.2 / WordPress 4.9.9 site, and at least once a minute I get this in my PHP error log:

Warning: count(): Parameter must be an array or an object that implements Countable in /home/nerdsw5/public_html/wp-content/plugins/wp-defender/app/module/ip-lockout/controller/main.php on line 544

Is this something I should be concerned with?