Hi Brian- have a quick question about a UIPropertyViewAnimator. I'm using one to apply a blur effect with a UIVisualEffectView in relation to a collection view's scroll offset. When I present another view controller modally, and return to the collection view, the UIPropertyViewAnimator can no longer change it's fractionComplete value like before, and seemingly becomes unresponsive. I tried to initialize a new one each time in viewDidAppear, but that doesn't really work too well. Curious if you know a good solution here?