Sorry forgot to write down server/game-id.
I had 3 coppers in hand, opponent had Highwayman in play, so I was affected by the attack.
When i click quick-buy on a $2 Peasant game plays two coppers and fails to buy the card, leaving me with $1 in play but also unable to play additional coppers for some reason.
A simple undo solved the situation this time, but i can imagine this bringing about similar issues in many types of games.