Solved as well
I've solved this issue as well.
The file /webassist/mail/mail_php.php contains the following line:
$_SESSION[$mailRef."_Log"] .= "Sending To: " .$mailTo . "... ";
I have changed it to:
$_SESSION[$mailRef."_Log"] = "Sending To: " .$mailTo . "... ";
Notice the period removed before the equal sign. This creates a new result for each email.
This should probably be added to the bug list.