It seems that the first AI member in a group actually can detect stairs and move up them, but only when I order the group to move to an actual building position. For example, if I am outside of the barracks building and order a "move there" and the cursor detects a building position, the first AI member will use the stairs and go up, but the members behind him will not. They still get very lost.

Any update on this? I am trying to finish the campaign so I can move onto Apex!