Found this interesseting bug by buffing myself levitate while standing on top of the gone chest ._.
Works in nHC an HC mode (maybe with every chest in WoW).
-Wait for the Chest
-Let your Mates jump on top of the chest
-Loot
-Wait till the chest is gone (they will float in mid air)
-Buff them levitate
-Profit
(Hopefully not a repost)