I had a grinder level give me exp but the chest never spawned , I would suggest that if a box is not looted you can wave at the rewards vendor back in town to get what you did not receive.
Have it for world boss chests too , I have seen the chest spawn died and returned to no chest.
Let’s extend it to dungeon chests , I’ve had chests at the end of a dungeon that have respawned mobs. Making the treck back (pug groups tend to cookie immediately) having to solo all the mobs to get back to my loot. That’s not fun. And it disuades me from playing with people I dont know.
I dont know about extending it to treasure map chests … O and deffinately dont apply it to trickster goblin >.<
(Like the mail man in other mmos most recently destiny)