I'm not sure if this is something I'm doing, or if it's because I haven't finished the full Campaign yet, but I keep encountering a problem when I try to replay some of the Campaign missions in the Danger Room.

When I add more heroes to a team where there was already one hero to begin with (like the mission where The Ant joins you to go after The Shadow), and I then start the mission, the only Hero that's there is the hero in the first team slot, so all I'm controlling is one hero for the whole mission.

Is this a bug, or am I doing something wrong that is causing this?

Sorry if that was a little confusing, but I couldn't think of any other way to describe the problem