On the most recent update, 2 new ST sets were added. Mistakenly, DECA made it such that the armor and ring of both of the sets could be forged without their usually required ST token. This led to them announcing the following:
However, if you had these items in the vault, they would stay. However, if they appear in any other location (such as the nexus, a dungeon key, etc), they will disappear. Additionally, you cannot break these items down in the Forge, and they have 0 feedpower.
This makes these items (in my opinion) the coolest collectable that we’ve had in a long, long time. They were only accessible for 20-28 hours. (I don’t know if this bug started happening as of the update, or as of the hotfix that occurred 8 hours after it.)