@Adriano Faria I can confirm I have this same issue. It seems to be fixed by me logging in as the submitter and simply resubmitting the tutorial. Not sure what happened but it is an issue on our side.
On an unrelated note...what I actually came here to post. I am recieveing this error when I try to enable guest access to the site. I am trying to create a guest page but to do it I have to disable the Tutorials App then enable guest access, then enable the tutorials app again. Unfortunately this method does not allow me to remove tutorials access for guest as it will throw the following error:
REPLACE INTO `tutorials_groups` ( `tutorials_g_id`, `tutorials_posts_access`, `tutorials_othermems`, `tutorials_copy`, `tutorials_tutorializepost`, `tutorials_viewreaders`, `tutorials_view` ) VALUES ( 2, NULL, NULL, NULL, NULL, NULL, true )
IPS\Db\Exception: Column 'tutorials_posts_access' cannot be null (1048)
#0 /var/www/html/106131/system/Db/Db.php(967): IPS\_Db->preparedQuery('/*r304709::r304...', Array)
#1 /var/www/sitefiles/r304709/applications/tutorials/sources/Members/Members.php(63): IPS\_Db->replace('tutorials_group...', Array)
#2 /var/www/sitefiles/r304709/applications/tutorials/extensions/core/GroupForm/Tutorials.php(75): IPS\tutorials\_Members::setGroupData(2, NULL, NULL, NULL, NULL, NULL, true)
#3 /var/www/html/106131/applications/core/modules/admin/members/groups.php(224): IPS\tutorials\extensions\core\GroupForm\_Tutorials->save(Array, Object(IPS\Member\Group))
#4 /var/www/html/106131/system/Dispatcher/Controller.php(90): IPS\core\modules\admin\members\_groups->form()
#5 /var/www/html/106131/applications/core/modules/admin/members/groups.php(39): IPS\Dispatcher\_Controller->execute()
#6 /var/www/html/106131/system/Dispatcher/Dispatcher.php(153): IPS\core\modules\admin\members\_groups->execute()
#7 /var/www/html/106131/admin/index.php(13): IPS\_Dispatcher->run()
#8 {main}