Where: Player-owned buildings
When: Unsure, think it has to do with the area.
What: Constructed a Ballista, and when dismantling it it would not disappear and in-fact gave a complete refund of the materials used. Could be used endlessly until Ballista was destroyed.
Recreate: Build a Ballista, specifically in a player-owned zone so far. Use a kit to dismantle it, it will just refund the wood, and the place-able. Think it has to placed before it is saved persistently.