Sometimes two wandering heroes bump into one another, and then they form an army and can't be recruited even when the little "..." icon pops up.

Also: there may be some strangeness with changing the name of the world and/or messing around a lot with character creation (eg, making a king, going back, making another one, going back etc) and spawning of goodie huts - in my first game it spawned bug-level craploads of goodie huts (like, a dozen morrigan towers, or so many notables that there would be two on one grid square) but it was my first game so I didn't realize anything was wrong.  Haven't tried to reproduce that one yet though.  Might also be an "initial run" bug.