Hi, Users are reporting issues with the unread functionality, whereby when clicking the thread title (eg. /threads/title.numeric/unread ) from the thread list, they are not taken to the last unread post, but instead to earlier posts. Some example user reports ... I have CDN active for images and js, as well as cacheSessions and backend Memcached I'm not familiar with how the functionality/mechanics of unread posts operates with XF, whether it's a database record, user cookie, webserver session variable, or combinations of these etc. How does one start to investigate and diagnose this issue?