So I'm playing through the game on hard (and really enjoying it too) and I've got to the part where you defend the fortress in the mountains from legions of astral soldiers.

I managed to get all my heroes down from the wall in dramatic fashion and brought them all to the control zone at the edge of the map, but I can't seem to fulfill the objective. Has anyone completed this, and if so how did you do it? I thought perhaps it was a bug but I'm not sure if you have to hold for a certain number of turns before the objective becomes complete.

Thanks for any help!


(edit: I think it is a bug because I tried again and killed all the enemies that came through the gate so I'm just cycling through the turns of my own characters waiting for an event.)