No Retreat Italy 3-player game

I have recently finished a 3-player game of No Retreat Italy on Vassal. Everything worked well up until the point when we were required to change sides due to an event. None of the players could flip their cards so we ended up having to ignore the event. Has anyone else had this problem?

Cards that are masked belong to the player that masked it. To give it to another player you must unflip your cards, then retire your side, select the other side (that your opponent has retired), and flip your new cards.