QtQuick Controls 2's Switch component shows disabled colours when enabled at creation

Adding a Switch that starts in an enabled condition ("position: 1") results it the switch being displayed in the on position, but being styled as if it was off. Clicking on the switch then results in the switch remaining in the current location but having the correct colours applied to it.

Here's a quick QML app demonstrating this:

main.qml

Expected result:

Actual result: