[philippehenri]

PS: if i reset the following line (from wp-includes/class_wp_rewrite.php, function rewrite_rules() )

$post_rewrite = $this->generate_rewrite_rules( $this->permalink_structure, EP_PERMALINK );

by adding “$post_rewrite=array();” after it , then the problem disappear. So this is clearly the rewrite rule created after the POST in activity that is causing the problem