diff --git a/AI/BattleAI/BattleExchangeVariant.cpp b/AI/BattleAI/BattleExchangeVariant.cpp
index 9846a6efe..f0a29682b 100644
--- a/AI/BattleAI/BattleExchangeVariant.cpp
+++ b/AI/BattleAI/BattleExchangeVariant.cpp
@@ -843,7 +843,7 @@ bool BattleExchangeEvaluator::checkPositionBlocksOurStacks(HypotheticBattle & hb
 					}
 				}
 
-				if(!reachable && vstd::contains(reachabilityMap[hex], unit))
+				if(!reachable && std::count(reachabilityMap[hex].begin(), reachabilityMap[hex].end(), unit) > 1)
 				{
 					blockingScore += ratio * (enemyUnit ? BLOCKING_OWN_ATTACK_PENALTY : BLOCKING_OWN_MOVE_PENALTY);
 				}