Make sure _globalMatrix is not set to false values in Item#rasterize().

src/item/Item.js

@@ -3160,7 +3160,9 @@ var Item = Base.extend(Callback, /** @lends Item# */{
 		var transforms = param.transforms,
 			parentMatrix = transforms[transforms.length - 1],
 			globalMatrix = parentMatrix.clone().concatenate(this._matrix);
-		transforms.push(this._globalMatrix = globalMatrix);
+		// Only keep track of transformation if told so. See Project#draw()
+		if (param.trackTransforms)
+			transforms.push(this._globalMatrix = globalMatrix);
 		// If the item has a blendMode or is defining an opacity, draw it on
 		// a temporary canvas first and composite the canvas afterwards.
 		// Paths with an opacity < 1 that both define a fillColor

src/project/Project.js

@@ -370,7 +370,12 @@ var Project = PaperScopeItem.extend(/** @lends Project# */{
 			offset: new Point(0, 0),
 			// A stack of concatenated matrices, to keep track of the current
 			// global matrix, since Canvas is not able tell us (yet).
-			transforms: [matrix]
+			transforms: [matrix],
+			// Tell the drawing routine that we want to track nested matrices
+			// in param.transforms, and that we want it to set _globalMatrix
+			// as used below. Item#rasterize() and Raster#getAverageColor() do
+			// not need to set this.
+			trackTransforms: true
 		});
 		for (var i = 0, l = this.layers.length; i < l; i++)
 			this.layers[i].draw(ctx, param);