Hi,
Quite straightforward process I would say. Installed plugin, selected one user to send an e-mail to, either using a custom template or no template. Disabled some plugins to see if the problems was in that area, but no. The only special thing is that i’m testing this locally through MAMP not using the STMP setting. When sending e-mails, the success message also displays twice on top of the page.
When I comment on of the following lines on line 956 or 1675 of wp-users-email.php out, the e-mail gets sent once. Getting one error and one success message on top the page.
$wau_status = wp_mail($wau_to[$j], $subject, $body, $headers);