Yep, that's right. They do. I have been aware of this for like... forever but had failed to report it. Usually you can summon one and when it dies it will ocasionally drop something like 11-17 gold. Not like it can be abused, it doesn't happen always, but i don't think it is intended.
Illusionary coins, as the ones the leprechuns drop in Harry Potter! Do they vanish after reset?!!? :O
Hey, there's an idea!
This probably should be under the exploitable bugs. Since it has the potential for free money.
Potentially, but i don't think you can make much with it. They don't always drop, instead they do so rarely, and it is not much gold the one they drop. I think people could earn 7 gold coins ever 27 minutes if they are lucky.