this same section of the map won't support "tower" upgrades. Sometimes they can be built and may stay through a restart and sometimes they revert back to just regular wall.
If they revert they have a chance of losing their bolt thrower upgrade.
I've spent a lot of crowns trying to test this or find a pattern to when you "lose" them, but i cannot tell what the trigger is. Its very random. Sometimes I have nothing left there but the small section of wall, sometimes i have a wall with bolt thrower, sometimes I have a tower there but the bolt thrower is missing.
I would guess the reserved space on the map for towers and homes is overlapping and causing each other to be destroyed.
edit: attached screen shot
Last edited by bandor : 04-05-2013 at 12:22 PM.