Talk:Quests/@comment-31.6.131.84-20191102144735/@comment-31.6.131.84-20191102150918

From the official blog, Sierra's comment: "You can't invest at all this update. When you next get a chance, you'll be able to open the ruins but the Incubus Pin will be gone."

So it looks like the same case as if with the Incubus King Armor in Chapter 2 - you can get it only if you do it ASAP. Or, in this case specifically, the last chance is after the Erosian War.