Null subject is an issue, causing a break and fail in the mark as read email, causing an infinite loop of task creation.
Fatal error: Uncaught TypeError: Kanboard\Plugin\Mailmagik\Action\ConvertEmailToTask::scanSubject(): Argument #1 ($subject) must be of type string, null given, called in /var/www/app/plugins/Mailmagik/Action/ConvertEmailToTask.php on line 155 and defined in /var/www/app/plugins/Mailmagik/Action/ConvertEmailToTask.php:189
Null subject is an issue, causing a break and fail in the mark as read email, causing an infinite loop of task creation.