How will it be possible to get the achievements "On the Clock" and "Crypt Champion" in the future? They're the ones about reaching level 25 in a specific dungeon, and now that dungeon is expired. Thanks!
Those achievements are meant to be rewards for completing the season when it's running.
It's on the to-do list to hide them if you didn't achieve them, as there will be new achievements featured with the future seasons.