Update: The devs have since acknowledged this as a Known Issue and it should be fixed in the future.
Original Post
As of 6.5 the Duty Finder hides Duty Roulette: Expert and Duty Roulette: Mentor for anyone who has not completed all the requirements. This is different from the old behavior where when new content was added Duty Roulette: Expert and Duty Roulette: Mentor would be greyed out and their information panes would tell you which duties you needed to complete to regain access to them, with ??? to prevent spoilers if you had not yet unlocked those duties.
The change in 6.5 is a bad UI/UX change. We've had many people in /novice asking what happened to their roulettes, and they wouldn't be asking if the behavior hadn't been changed.
It might sound simple enough to tell them "do the new content" whenever a new patch comes out, but patch days are few and far between compared to the long periods between patches during which they will have access to roulettes once unlocked, and so patch days with the sudden disappearance of options from the Duty Roulette will always be jarring and will always result in many people asking what happened to their roulettes.
The removal of greyed out DR: Mentor is also the removal of the only in-game checklist of everything that needs to be done for DR:Mentor, which means people now have to look outside the game for a checklist if they're not sure what requirements they're missing.
Please revert this change so that DR: Expert and DR: Mentor appear greyed out with a list of their unfulfilled requirements.