QML EaseFollow does not work on the 0-1 range

I'm trying to use an EaseFollow element to animate the opacity of a rectangle, however this does not work. It seems like EaseFollow is operating on integers only, or something like that.

Attached is an example that does not work (click the rectangle to make it appear or hide, it won't be animated). I've also provided two alternative approaches that work fine, for comparison.