Battlegrounds (triple reward bug)

in battlegrounds , using Demon Hunter ,
finished the quest called “Victim’s specter”.
After golden Imprisoner died and deathrattle : summon a normal 2/2 imp.
2/2 imp become the last die at the battle.

The Victim’s specter trigger "get a plain copy of the last friendly minion that dead. It copied normal 2/2 imp to my hand.

After i played normal 2/2 imp, bartender give me a triple reward.
Next round. I played a normal 2/2 imp on table and it become last die.

It give me triple reward again …

Same battle the normal mircrorobot become last dead and copy to my hand. No bug happen. I think imp only ?

This bug also works with golden rats from ratpack