During gambling for items, I threw a ring to sell it at the same time as the rng for another ring was going on, and it gave me the money for the sold ring and the ring itself back.
I counted my gold and did it again, as seen in the clip - more money, and item back. This can become a big issue.
I think this is an issue with the service, if you do that, try going teleporting to another town or waypoint and see if your gold is still showing like that.
You can “duplicate” runes and glyphs but it appears to be user side only, so when you go to a new location, your inventory is updated from the server.