Cannot override default anchors in item

See attached example.

In MyItem.qml definition, we set anchors.left: parent.left, and when instantiating it, we override it as anchors.left: text.right. The expected result would be to see the red translucent rectangle on the right side of the text, instead it stays anchored to the main item's left side. (Incidentally, anchor margins can be overridden. My mistake, they can't).