I recently bought a Treasure Hunting mission from the Auction House. When I used it, I noticed the name of a new mission with a little unlocked lock appear next to it in my Treasure Hunt mission list.
However, once that mission was done, it doesn't appear in my list any more.
Is that mission only doable once, or is there some sort of limit (time or # of missions) before it reappears in my list?
I ask because the loot from said mission was much better than normal.