Far as i noticed, goblin steal the first "Steal-able" item in the list, for example, lets say you start with 2x potion 10, and 1x potion 20, when goblin steal you and fight end, you end up with 1x potion 10 AND if you steal the goblin back you WONT get the item back, sadly changing the order item in sortion option doesn't change the order of items the way goblin steal stuffs so welp. Now those "Steal-able" items tend to be consumables that you get from stores like potions but now that you mention it, would be good if someone was able to test it further
And i think stolen items can't be sold in any store for the label of STOLEN, that's why i recommend to only steal the most necesary items, since you won't be able to obtain any profit for stealing more.