Index: binaries/data/mods/public/simulation/components/Garrisonable.js
===================================================================
--- binaries/data/mods/public/simulation/components/Garrisonable.js
+++ binaries/data/mods/public/simulation/components/Garrisonable.js
@@ -23,6 +23,10 @@
 	if (this.holder)
 		return false;
 
+	let cmpUnitAI = Engine.QueryInterface(this.entity, IID_UnitAI);
+	if (cmpUnitAI)
+		cmpUnitAI.SetGarrisoned(true);
+
 	this.holder = entity;
 	return true;
 };
@@ -32,6 +36,10 @@
  */
 Garrisonable.prototype.UnGarrison = function()
 {
+	let cmpUnitAI = Engine.QueryInterface(this.entity, IID_UnitAI);
+	if (cmpUnitAI)
+		cmpUnitAI.SetGarrisoned(false);
+
 	delete this.holder;
 };
 
Index: binaries/data/mods/public/simulation/components/UnitAI.js
===================================================================
--- binaries/data/mods/public/simulation/components/UnitAI.js
+++ binaries/data/mods/public/simulation/components/UnitAI.js
@@ -626,7 +626,7 @@
 			this.SetNextState("IDLE");
 			return;
 		}
-		else if (this.IsGarrisoned())
+		else if (this.isGarrisoned)
 		{
 			if (this.IsAnimal())
 				this.SetNextState("ANIMAL.GARRISON.GARRISONED");
@@ -649,7 +649,7 @@
 
 	"Order.Ungarrison": function() {
 		this.FinishOrder();
-		this.isGarrisoned = false;
+		delete this.isGarrisoned;
 	},
 
 	"Order.Cheer": function(msg) {
@@ -3102,8 +3102,16 @@
 						return true;
 					}
 
-					if (this.IsGarrisoned())
+					// Called when autogarrisoning.
+					if (this.isGarrisoned)
+					{
+						if (this.IsTurret())
+						{
+							this.SetNextState("IDLE");
+							return true;
+						}
 						return false;
+					}
 
 					if (this.CanGarrison(target))
 						if (this.CheckGarrisonRange(target))
@@ -3111,7 +3119,6 @@
 							var cmpGarrisonHolder = Engine.QueryInterface(target, IID_GarrisonHolder);
 							if (cmpGarrisonHolder.Garrison(this.entity))
 							{
-								this.isGarrisoned = true;
 								this.SetImmobile(true);
 
 								if (this.formationController)
@@ -3448,7 +3455,6 @@
 	this.orderQueue = []; // current order is at the front of the list
 	this.order = undefined; // always == this.orderQueue[0]
 	this.formationController = INVALID_ENTITY; // entity with IID_Formation that we belong to
-	this.isGarrisoned = false;
 	this.isIdle = false;
 	this.isImmobile = false; // True if the unit is currently unable to move (garrisoned,...)
 
@@ -3505,14 +3511,22 @@
 	return this.isIdle;
 };
 
+/**
+ * Whether the entity is garrisoned (according to UnitAI).
+ * This is only called from outside UnitAI for performance reasons,
+ * if in the future it should return anything else than just the member,
+ * all calls to this.isGarrisoned here in UnitAI ought to be updated.
+ *
+ * @return {boolean} Whether the entity is garrisoned.
+ */
 UnitAI.prototype.IsGarrisoned = function()
 {
-	return this.isGarrisoned;
+	return !!this.isGarrisoned;
 };
 
-UnitAI.prototype.SetGarrisoned = function()
+UnitAI.prototype.SetGarrisoned = function(garrisoned)
 {
-	this.isGarrisoned = true;
+	this.isGarrisoned = garrisoned;
 };
 
 UnitAI.prototype.GetGarrisonHolder = function()
@@ -3845,7 +3859,7 @@
 	this.order = this.orderQueue[0];
 
 	let cmpPosition = Engine.QueryInterface(this.entity, IID_Position);
-	if (this.orderQueue.length && (this.IsGarrisoned() || this.IsFormationController() ||
+	if (this.orderQueue.length && (this.isGarrisoned || this.IsFormationController() ||
 	        cmpPosition && cmpPosition.IsInWorld()))
 	{
 		let ret = this.UnitFsm.ProcessMessage(this,
@@ -4040,7 +4054,7 @@
 			this.UpdateWorkOrders(type);
 	}
 
-	let garrisonHolder = this.IsGarrisoned() && type != "Ungarrison" ? this.GetGarrisonHolder() : null;
+	let garrisonHolder = this.isGarrisoned && type != "Ungarrison" ? this.GetGarrisonHolder() : null;
 
 	// Do not replace packing/unpacking unless it is cancel order.
 	// TODO: maybe a better way of doing this would be to use priority levels
@@ -4141,7 +4155,7 @@
 	if (this.workOrders.length == 0)
 		return false;
 
-	if (this.IsGarrisoned())
+	if (this.isGarrisoned)
 	{
 		let cmpGarrisonHolder = Engine.QueryInterface(this.GetGarrisonHolder(), IID_GarrisonHolder);
 		if (!cmpGarrisonHolder || !cmpGarrisonHolder.PerformEject([this.entity], false))
@@ -5287,7 +5301,7 @@
 	{
 		// May happen if an order arrives on the same turn the unit is garrisoned
 		// in that case, just forget the order as this will lead to an infinite loop
-		if (this.IsGarrisoned() && !this.IsTurret() && type != "Ungarrison")
+		if (this.isGarrisoned && !this.IsTurret() && type != "Ungarrison")
 			return;
 		this.ReplaceOrder(type, data);
 	}
@@ -5522,7 +5536,7 @@
  */
 UnitAI.prototype.Ungarrison = function()
 {
-	if (this.IsGarrisoned())
+	if (this.isGarrisoned)
 	{
 		this.SetImmobile(false);
 		this.AddOrder("Ungarrison", null, false);
@@ -5534,7 +5548,6 @@
  */
 UnitAI.prototype.Autogarrison = function(target)
 {
-	this.isGarrisoned = true;
 	this.PushOrderFront("Garrison", { "target": target });
 };
 
Index: binaries/data/mods/public/simulation/components/tests/test_Garrisonable.js
===================================================================
--- binaries/data/mods/public/simulation/components/tests/test_Garrisonable.js
+++ binaries/data/mods/public/simulation/components/tests/test_Garrisonable.js
@@ -1,4 +1,5 @@
 Engine.LoadComponentScript("interfaces/Garrisonable.js");
+Engine.LoadComponentScript("interfaces/UnitAI.js");
 Engine.LoadComponentScript("Garrisonable.js");
 
 const garrisonHolderID = 1;
Index: binaries/data/mods/public/simulation/helpers/Transform.js
===================================================================
--- binaries/data/mods/public/simulation/helpers/Transform.js
+++ binaries/data/mods/public/simulation/helpers/Transform.js
@@ -78,8 +78,6 @@
 				cmpNewUnitAI.SetGuardOf(guarded);
 			}
 		}
-		if (cmpUnitAI.IsGarrisoned())
-			cmpNewUnitAI.SetGarrisoned();
 	}
 
 	let cmpPromotion = Engine.QueryInterface(oldEnt, IID_Promotion);