diff --git a/src/main/java/noppes/npcs/client/gui/mainmenu/GuiNpcAI.java b/src/main/java/noppes/npcs/client/gui/mainmenu/GuiNpcAI.java
index 1abd1cdd1..dd95ceab9 100644
--- a/src/main/java/noppes/npcs/client/gui/mainmenu/GuiNpcAI.java
+++ b/src/main/java/noppes/npcs/client/gui/mainmenu/GuiNpcAI.java
@@ -141,7 +141,7 @@ public class GuiNpcAI extends GuiNPCInterface2 implements ITextfieldListener, IG
 		}
 		else if (button.id == 17) {
 			ai.tacticalVariant = EnumNavType.values()[button.getValue()];
-			ai.directLOS = EnumNavType.values()[button.getValue()] == EnumNavType.Stalk ? false : this.ai.directLOS;
+			ai.directLOS = EnumNavType.values()[button.getValue()] != EnumNavType.Stalk && this.ai.directLOS;
 			initGui();
 		}
 		else if (button.id == 22) {
diff --git a/src/main/java/noppes/npcs/entity/EntityNPCInterface.java b/src/main/java/noppes/npcs/entity/EntityNPCInterface.java
index 2d029b97c..f9419d802 100644
--- a/src/main/java/noppes/npcs/entity/EntityNPCInterface.java
+++ b/src/main/java/noppes/npcs/entity/EntityNPCInterface.java
@@ -434,7 +434,11 @@ public abstract class EntityNPCInterface extends EntityCreature implements IEnti
 
 	protected void updateAITasks()
 	{
-		super.updateAITasks();
+		try {
+			super.updateAITasks();
+		} catch (ConcurrentModificationException ignored){
+		}
+
 		this.getNavigator().onUpdateNavigation();
 		this.getMoveHelper().onUpdateMoveHelper();
 	}
diff --git a/src/main/java/noppes/npcs/scripted/entity/ScriptNpc.java b/src/main/java/noppes/npcs/scripted/entity/ScriptNpc.java
index 6e5bef216..a777901ae 100644
--- a/src/main/java/noppes/npcs/scripted/entity/ScriptNpc.java
+++ b/src/main/java/noppes/npcs/scripted/entity/ScriptNpc.java
@@ -613,10 +613,11 @@ public class ScriptNpc<T extends EntityNPCInterface> extends ScriptLiving<T> imp
 	}
 
 	public void setTacticalVariant(int variant){
-		if(variant > EnumNavType.values().length-1)
+		if(variant > EnumNavType.values().length-1 || variant < 0)
 			return;
 
 		npc.ai.tacticalVariant = EnumNavType.values()[variant];
+		npc.ai.directLOS = EnumNavType.values()[variant] != EnumNavType.Stalk && npc.ai.directLOS;
 	}
 
 	public int getTacticalVariant(){