ObjectLoader: Use instanceColor.itemSize

src/loaders/ObjectLoader.js

@@ -965,7 +965,7 @@ class ObjectLoader extends Loader {
 
 				object = new InstancedMesh( geometry, material, count );
 				object.instanceMatrix = new BufferAttribute( new Float32Array( instanceMatrix.array ), 16 );
-				if ( instanceColor !== undefined ) object.instanceColor = new BufferAttribute( new Float32Array( instanceColor.array ), 3 );
+				if ( instanceColor !== undefined ) object.instanceColor = new BufferAttribute( new Float32Array( instanceColor.array ), instanceColor.itemSize );
 
 				break;