Makes AI see through stealth better.

If AI gains LoS for the first time but fails to spot you, they treat it
as if they haven't seen you for 10 turns, instead of as if they had
spotted you that turn.

game/engines/default/engine/interface/ActorAI.lua

@@ -163,8 +163,14 @@ function _M:aiSeeTargetPos(target)
 	local LSeen = self.ai_state.target_last_seen
 	if type(LSeen) ~= "table" then return tx, ty end
 	local spread = 0
-	LSeen.GCache_turn = LSeen.GCache_turn or game.turn -- Guess Cache turn to update position guess (so it's consistent during a turn)
-	LSeen.GCknown_turn = LSeen.GCknown_turn or game.turn -- Guess Cache known turn for spread calculation (self.ai_state.target_last_seen.turn can't be used because it's needed by FOV code)
+
+	-- Guess Cache turn to update position guess (so it's consistent during a turn)
+	-- Start at -1000 to make sure ti gets run the first time.
+	LSeen.GCache_turn = LSeen.GCache_turn or game.turn - 1000
+
+	-- Guess Cache known turn for spread calculation (self.ai_state.target_last_seen.turn
+	-- can't be used because it's needed by FOV code)
+	LSeen.GCknown_turn = LSeen.GCknown_turn or game.turn - 1000
 
 	-- Check if target is currently seen
 	local see, chance = self:canSee(target)
@@ -187,4 +193,4 @@ function _M:aiSeeTargetPos(target)
 		if LSeen.GCache_x then return LSeen.GCache_x, LSeen.GCache_y end
 	end
 	return tx, ty -- Fall through to correct coords
-end
\ No newline at end of file
+end