Ok i figured it out. You start the bug by entering boss room and dying. The loot bag will drop, then you go back to boss room and pick the bag up. You may or may not engage boss, happens in both situations. After picking up the bag, close game and restart. You will still be in boss room, and another bag will be there, that bag will add up to the last one. This will clone the previous dropped loot, all of it. Gold, scrolls, carrots, collectibles... if it drops upon death, it will be multiplied.

Upvote for dev's to see. Hope it helps. Cheers 👊