Shape animation works in SwiftUI but not when embedded in UIKit

The title pretty much says everything, and the easiest would be to check the code example. See on GitHub here

Just change complexShape: false for true line 103 in ViewController.swift, the SwiftUI live preview works properly but when running the app, the SwiftUI View is embedded in a UIView and the animation won't work.

Obviously 'withAnimation' isn't called from UIKit and that could be the problem, but a simple shape is animated properly... any expert @ Apple could help out here ?
Shape animation works in SwiftUI but not when embedded in UIKit
 
 
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