Hey, i have noticed serveral times that people opens hunt rift and be afk or waiting until other players closed the rift for them and at a time they run around and loot the extra loot chests with the epic items.
IMO its a bit unfair to let someone elso do the work 4 you and later you get the loot.

here is an example of what i mean:

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there someone else have open a hunt rift but there was no one in the area and after i have made a hunt rift on same place i have got my chest.

Maybe make an counter after the chests disappear.

Best wishes!