Yes, and after upgrading to the latest app version you uploaded earlier i now get this error
the added note is still saved
Error: Call to a member function addToStack() on null (0)
#0 [internal function]: IPS\Theme\email_html_membernotes_notification_member_note(Object(IPS\Member), Object(IPS\Email\Outgoing\Smtp))
#1 /IPB/system/Email/Email.php(632): call_user_func_array('IPS\\Theme\\email...', Array)
#2 IPB/system/Email/Email.php(269): IPS\_Email::template('membernotes', 'notification_me...', 'html', Array)
#3 IPB/system/Email/Email.php(561): IPS\_Email->compileContent('html', Object(IPS\Member), Object(IPS\Lang))
#4 IPB/system/Notification/Notification.php(499): IPS\_Email->mergeAndSend(Array, NULL, NULL, Array, Object(IPS\Lang))
#5 IPB/system/Notification/Notification.php(480): IPS\_Notification->sendEmails(Array, Array)
#6 IPB/applications/membernotes/modules/front/notes/notes.php(162): IPS\_Notification->send()
#7 [internal function]: IPS\membernotes\modules\front\notes\_notes->add()
#8 IPB/system/Dispatcher/Controller.php(85): call_user_func(Array)
#9 IPB/system/Dispatcher/Dispatcher.php(129): IPS\Dispatcher\_Controller->execute()
#10 IPB/index.php(13): IPS\_Dispatcher->run()
#11 {main}