1st time posting...hello!
Story time: So after a quick run to China, I put some of my found ore on one of those monsters of a display case. Carter's XL edition. I was in live mode, paused for ease of mind so I didn't have to worry about my sims catching fire or something. I noticed a bar out of place, and thought twice about arranging it. Being in live mode (in the inventory tab) I dragged said silver bar onto the little "sell" button for a whole 45 bucks. Funny thing is, it didn't disappear. After like...4 I got curious and dragged it into my inventory. It disappeared from the case, but wouldn't go away from my inventory. Did that for another 5 or 6. Dragged it back onto the case and did another couple sells.
And no, it wasn't stacked. I know a dang stack when I see one.
Lasted until I went "huh...weird." and unpaused. Sadly, my slow little money maker was finally gone. Time to save and try with something a bit more expensive