My client has an issue with Popular Posts. When we clear the cache of the plugin (the site does not use a seperate caching plugin) and we click some posts, all goes well. For some time the popular posts are shown correctly, but after some time old posts from 2013 are shown. These old posts do not show up in the stats at /wp-admin/options-general.php?page=wordpress-popular-posts
How can we make sure that the old posts do not show up? You can log in to http://dejlig.nl/wp-admin with the credentials I have sent you before.