Happening to me, too. I have 3 missions currently, the right most mission keeps switching what map it wants me to play. Edit: Finally was able to complete it. I kept switching maps, trying to anticipate what it would want me to play. After about 40-50 load screens finally loaded into Ramparts, with a Dragonfall Castle quest. I was able to select "replay" it after the first win without it changing on me twice.