Fatal Error when duplicating a published post

Hi, any idea how to fix the following error when duplicating an existing and published post? For me it sounds quite weird, sorry 🙂

Regards,

Peter

Fatal error : Uncaught Error: The script tried to modify a property on an incomplete object. Please ensure that the class definition “Wpil_Model_Link” of the object you are trying tooperate on was loaded before unserialize() gets called or provide an autoloader to loadthe class definition in /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/formatting.php:5131 Stack trace: #0 /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/formatting.php(5126): map_deep() #1 /var/www/web85/htdocs/peter-auf-tour.de/wp-content/plugins/duplicate-post/admin-functions.php(400): map_deep() #2/var/www/web85/htdocs/peter-auf-tour.de/wp-content/plugins/duplicate-post/admin-functions.php(424): duplicate_post_addslashes_deep() #3 /var/www/web85/htdocs/peter-auf-tour.de/wp-content/plugins/duplicate-post/admin-functions.php(386):duplicate_post_wp_slash() #4 /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/class-wp-hook.php(326): duplicate_post_copy_post_meta_info() #5/var/www/web85/htdocs/peter-auf-tour.de/wp-includes/class-wp-hook.php(348):WP_Hook->apply_filters() #6 /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/plugin.php(517): WP_Hook->do_action() #7 /var/www/web85/htdocs/peter-auf-tour.de/wp-content/plugins/duplicate-post/admin-functions.php(721): do_action() #8/var/www/web85/htdocs/peter-auf-tour.de/wp-content/plugins/duplicate-post/src/handlers/link-handler.php(143): duplicate_post_create_duplicate() #9/var/www/web85/htdocs/peter-auf-tour.de/wp-includes/class-wp-hook.php(324):Yoast\WP\Duplicate_Post\Handlers\Link_Handler->clone_link_action_handler() #10/var/www/web85/htdocs/peter-auf-tour.de/wp-includes/class-wp-hook.php(348):WP_Hook->apply_filters() #11 /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/plugin.php(517): WP_Hook->do_action() #12 /var/www/web85/htdocs/peter-auf-tour.de/wp-admin/admin.php(420): do_action() #13 {main} thrown in /var/www/web85/htdocs/peter-auf-tour.de/wp-includes/formatting.php
on line 5131

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