[FB13265427] ScrollView + LazyVStack is jittery starting with iOS 17

FB13265427.md

When a LazyVStack is nested within a ScrollView on iOS 17, the scroll view's content offset can be incorrectly set for a brief moment, causing the scroll view to "jitter".

Here's some sample code:

import SwiftUI

struct ContentView: View {
    @State var isExpanded = Set<Int>()
    var body: some View {
        ScrollView {
            LazyVStack {
                ForEach(0..<10, id: \.self) { index in
                    Rectangle()
                        .fill(.orange)
                        .overlay {
                            Text("\(index)")
                                .font(.title)
                        }
                        .frame(height: isExpanded.contains(index) ? 200 : 100)
                        .onTapGesture {
                            withAnimation {
                                if isExpanded.contains(index) {
                                    isExpanded.remove(index)
                                } else {
                                    isExpanded.insert(index)
                                }
                            }
                        }
                        .padding(.bottom, 10)
                }
            }
        }
    }
}

To reproduce, run the provided sample code on an iOS 17 simulator or device and follow these steps:

1. Tap 1
2. Tap 3
3. Scroll down
4. Tap 7

When tapping 7, notice how the scrollview shifts up an back down for a split second.

This bug does not happen on iOS 16.4, but does happen on iOS 17.0. Changing the LazyVStack for a VStack also avoids the issue.

This was tested with Xcode Version 15.0 (15A240d) running on an iPhone SE (3rd generation) running iOS 17.0 (21A328).