Hello there Thanks for the report. This sounds less like the mission itself is still waiting to be completed, and more like account-scoped Destined Heroes / Dyadic Prism progression got into an awkward state. Destined Heroes, along with Lost in the Light and Found in the Dark, can only be completed once per account. On additional characters, players are expected to use the six Adventures in the Lost City to unlock the rest of their Prismatic abilities rather than re-running those quests normally. We have also seen a separate issue where players could end up with a Dyadic Prism stuck on an alternate character after obtaining Ergo Sum elsewhere, with no landing zone available to redeem it. Because of that, if you already got credit for the mission earlier through another run or character, the missing Sacrarium landing zone and the leftover Prism would be consistent with that kind of progression state rather than the mission still being available to launch normally. So if your main goal is replaying that mission through Destined Heroes, I do not believe that questline is meant to be restorable on that character once the account has already completed it. If you want to help narrow this down further, the most useful detail would be whether Ergo Sum was already earned on another character before this character picked up the Dyadic Prism.