Activation email not sent to new users on Windows (have come out another time)

[axewww]

​https://wordpress.org/support/topic/activation-email-not-sent-to-users/#post-9009273
I experience this into a: windowsOS/php5.6/apache2.4
when i test an user registration, the email that inform the admin about new user is sent out, while the activation email to the user not.
so to fix it on fly, i've remove (like last time) $header that seem to cause a problem:

<?php
        //Can't use additional_parameters in safe_mode, calling mail() with null params breaks
        //@link http://php.net/manual/en/function.mail.php
        if (ini_get('safe_mode') or !$this->UseSendmailOptions or is_null($params)) {
            //$result = @mail($to, $subject, $body, $header);
            $result = @mail($to, $subject, $body);
        } else {
            $result = @mail($to, $subject, $body, $header, $params);
        }
        return $result;

[SergeyBiryukov]

Related: #20970, #21738, #37881.