The first delegated item when using Button from QtQuickControls 2 always missing its background

With the current Qt 5.9.4, when using component from QtQuickControls 2, the delegated item is not correctly delegated.

Simple use case:

ListView {
    id: listView

    width: 50
    model: 3

    delegate: Button {
        width: listView.width
        height: 3
        text: "foo"
    }
}

with Qt 5.9.4 , the first delegated item won't have any background but the second and third one will have their background.