Hi,
Did you find any solution about this problem ? I have the same problem, same line, same error :
Warning: Creating default object from empty value in /homepages/6/d310147084/htdocs/wp-admin/includes/post.php on line 732
Warning: Cannot modify header information - headers already sent by (output started at /homepages/6/d310147084/htdocs/wp-admin/includes/post.php:732) in /homepages/6/d310147084/htdocs/wp-admin/admin-header.php on line 9
I was with wordpress 5.5.3. I updated my themes and all other suggested updates disapears (I add plugins and wordpress update which was pending). I disabled all themes and plugins, with no success. I manualy update to wordpress 5.6 and deleted (from wp-content) all recently updated plugins and themes. No more success. Same error remain only when I’m on add articles or pages, no error in other admin pages.
Thank you for any advice !
