In game 3154258, I bought a Mint with potion in hand (I think). It trashed my potion. My intention was not to play the potion so that it wouldn't be trashed. I didn't notice it until my potion didn't show up for a few turns.
In any case, if it happened how I think it did, it's a bug with mint. Also possible that I clicked autoplay, but I suspect maybe I didn't, so I report it.
Thanks for reporting it, but looking at the game log you actually played the potion (probably with Autoplay):
Turn 10:
...
(It says I instead of S because when loading your game I took your position)
I plays a Candlestick Maker.
I plays a Potion and 3 Coppers.
I buys a Mint.
I trashes 3 Coppers and a Potion.
I gains a Mint.
...
"I would have gotten away with it, too, if it hadn't been for that meddling Autoplay."
Thanks for checking. I can't check, being a lowly owner of base and intrigue only.