Index: binaries/data/mods/public/simulation/components/ResourceGatherer.js
===================================================================
--- binaries/data/mods/public/simulation/components/ResourceGatherer.js
+++ binaries/data/mods/public/simulation/components/ResourceGatherer.js
@@ -294,22 +294,32 @@
 
 /**
  * Transfer our carried resources to our owner immediately.
- * Only resources of the given types will be transferred.
- * (This should typically be called after reaching a dropsite).
+ * Only resources of the appropriate types will be transferred.
+ * (This should typically be called after reaching a dropsite.)
+ *
+ * @param {number} target - The target entity ID to drop resources at.
  */
-ResourceGatherer.prototype.CommitResources = function(types)
+ResourceGatherer.prototype.CommitResources = function(target)
 {
+	let cmpResourceDropsite = Engine.QueryInterface(target, IID_ResourceDropsite);
+	if (!cmpResourceDropsite)
+		return;
+
 	let cmpPlayer = QueryOwnerInterface(this.entity);
+	if (!cmpPlayer)
+		return;
 
-	if (cmpPlayer)
-		for (let type of types)
-			if (type in this.carrying)
-			{
-				cmpPlayer.AddResource(type, this.carrying[type]);
-				delete this.carrying[type];
-			}
+	let changed = false;
+	for (let type in this.carrying)
+		if (cmpResourceDropsite.AcceptsType(type))
+		{
+			cmpPlayer.AddResource(type, this.carrying[type]);
+			delete this.carrying[type];
+			changed = true;
+		}
 
-	Engine.PostMessage(this.entity, MT_ResourceCarryingChanged, { "to": this.GetCarryingStatus() });
+	if (changed)
+		Engine.PostMessage(this.entity, MT_ResourceCarryingChanged, { "to": this.GetCarryingStatus() });
 };
 
 /**
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
@@ -581,18 +581,16 @@
 		// Check if the dropsite is already in range
 		if (this.CheckTargetRange(this.order.data.target, IID_ResourceGatherer) && this.CanReturnResource(this.order.data.target, true))
 		{
-			var cmpResourceDropsite = Engine.QueryInterface(this.order.data.target, IID_ResourceDropsite);
-			if (cmpResourceDropsite)
+			let cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
+			if (cmpResourceGatherer)
 			{
-				// Dump any resources we can
-				var dropsiteTypes = cmpResourceDropsite.GetTypes();
+				cmpResourceGatherer.CommitResources(this.order.data.target);
 
-				Engine.QueryInterface(this.entity, IID_ResourceGatherer).CommitResources(dropsiteTypes);
 				// Stop showing the carried resource animation.
 				this.SetDefaultAnimationVariant();
 
 				// Our next order should always be a Gather,
-				// so just switch back to that order
+				// so just switch back to that order.
 				this.FinishOrder();
 				return;
 			}
@@ -2704,20 +2702,16 @@
 					// (we didn't get stopped before reaching it)
 					if (this.CheckTargetRange(this.order.data.target, IID_ResourceGatherer) && this.CanReturnResource(this.order.data.target, true))
 					{
-						let cmpResourceDropsite = Engine.QueryInterface(this.order.data.target, IID_ResourceDropsite);
-						if (cmpResourceDropsite)
+						let cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
+						if (cmpResourceGatherer)
 						{
-							// Dump any resources we can
-							let dropsiteTypes = cmpResourceDropsite.GetTypes();
-
-							let cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
-							cmpResourceGatherer.CommitResources(dropsiteTypes);
+							cmpResourceGatherer.CommitResources(this.order.data.target);
 
 							// Stop showing the carried resource animation.
 							this.SetDefaultAnimationVariant();
 
 							// Our next order should always be a Gather,
-							// so just switch back to that order
+							// so just switch back to that order.
 							this.FinishOrder();
 							return;
 						}
@@ -2906,12 +2900,10 @@
 
 				// Drop any resource we can if we are in range when the construction finishes
 				let cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
-				let cmpResourceDropsite = Engine.QueryInterface(msg.data.newentity, IID_ResourceDropsite);
-				if (cmpResourceGatherer && cmpResourceDropsite && this.CheckTargetRange(msg.data.newentity, IID_Builder) &&
+				if (cmpResourceGatherer && this.CheckTargetRange(msg.data.newentity, IID_Builder) &&
 					this.CanReturnResource(msg.data.newentity, true))
 				{
-					let dropsiteTypes = cmpResourceDropsite.GetTypes();
-					cmpResourceGatherer.CommitResources(dropsiteTypes);
+					cmpResourceGatherer.CommitResources(msg.data.newentity);
 					this.SetDefaultAnimationVariant();
 				}
 
@@ -2951,6 +2943,7 @@
 				// the build command should look for nearby resources to gather
 				if ((oldData.force || oldData.autoharvest) && this.CanReturnResource(msg.data.newentity, false))
 				{
+					let cmpResourceDropsite = Engine.QueryInterface(msg.data.newentity, IID_ResourceDropsite);
 					let types = cmpResourceDropsite.GetTypes();
 					let pos;
 					let cmpPosition = Engine.QueryInterface(msg.data.newentity, IID_Position);
@@ -3066,18 +3059,12 @@
 									}
 								}
 
-								// Check if we are garrisoned in a dropsite
-								var cmpResourceDropsite = Engine.QueryInterface(target, IID_ResourceDropsite);
-								if (cmpResourceDropsite && this.CanReturnResource(target, true))
+								// Check if we are garrisoned in a dropsite.
+								let cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
+								if (cmpResourceGatherer && this.CanReturnResource(target, true))
 								{
-									// Dump any resources we can
-									var dropsiteTypes = cmpResourceDropsite.GetTypes();
-									var cmpResourceGatherer = Engine.QueryInterface(this.entity, IID_ResourceGatherer);
-									if (cmpResourceGatherer)
-									{
-										cmpResourceGatherer.CommitResources(dropsiteTypes);
-										this.SetDefaultAnimationVariant();
-									}
+									cmpResourceGatherer.CommitResources(target);
+									this.SetDefaultAnimationVariant();
 								}
 
 								// If a pickup has been requested, remove it