4 ascendancy (trial of shaos)

You need to place 3 fates in doors after 3rd boss to be able to finish 4 ascendancy. And you actually need to have all 3 fates in your inventory (if you buy them let's say), not in stash. Because there is no stash in room with that doors. WHY?

In the bright sight, you can put them in that door as you get them, they will be there between attempts. But sure, stash would be nice, I had similar problem.