Comment 13 for bug 858292

That assert pointed me in the correct direction. All that needed doing in the end is increasing the area that the map is recalculated

@lowne: Thanks for all those screenshots, they were invaluable :)

The savegame is unrecoverable, so I'm attaching a savegame with an earlier state of the game. Play as red player and delete the small military buildings close to the border, or play as blue and conquer them.