I had a similar issue in single-player. In Cyseal, I chose to fight the merchant who admits to using sourcery in the upstairs room of the King Crab. She charmed Madora. When it was Madora's turn, I couldn't do anything. I tried skipping the turn, but that didn't work. I waited about 5 min to see if it would move on, but it didn't, and I had to reload.
So it seems like this is a bug.