Trying to access array offset on value of type bool 1

So on line ithemeland-free-gifts-for-woo/frontend/class/check_rule_condition.php:48 the code is executed also if it isn’t the checkout.

Patching the line as:
if (!isset($rules['items']) || !is_array($rules['items']) || count($rules['items']) <= 0) {

Fix the issue.