So i was rolling minion weapons at the gambler, eventually i picked up speed and sold while gambling and the items duped back.
So what I noticed happened was that during the time the gambler is rolling your item, anything you sell in your inventory during that period will respawn in your inventory when the item is rolled and placed in your inventory. Curious as a was i picked a few legendaries from my chest and sold them during the gamble time aswell, they all respawned in the inventory. Hence infinite gold dupe, i mean its not profitable at all unless you set up some kind of bot to autosell everything in your inventory but i figured id report it.
TL;DR When you gamble an item, anything you sell in your inventory respawns.