How to diagnose infinite layout loop

Due to limitations of SwiftUI VSplitView, and to preserve the appearance of the old C++/AppKit app I'm porting to SwiftUI, I rolled my own pane divider. It worked well on macOS 11, but after updating to macOS 12, it now triggers an infinite loop somewhere. Running the code below in an Xcode playground works for a short while, but if you wiggle the mouse up and down, after a few seconds it will get caught in an infinite loop:

import SwiftUI
import PlaygroundSupport
import AppKit
import CoreGraphics

PlaygroundPage.current.setLiveView(ContentView())

struct ContentView: View {
    @State var position: Double = 50

    var body: some View {
        VStack(spacing: 0) {
            Color.red
            .frame(maxHeight: position)
            PaneDivider(position: $position)
            Color.blue
        }
        .frame(width: 500, height:500)
    }
}

struct PaneDivider: View {
    @Binding var position: Double
    @GestureState private var isDragging = false // Will reset to false when dragging has ended

    var body: some View {
        Group {
            Divider()
            ZStack {
                Rectangle().fill(Color(white: 0.99))
                Circle().frame(width: 6, height: 6).foregroundColor(Color(white: 0.89))
            }.frame(height: 8)
            Divider()
        }
        .gesture(DragGesture()
            .onChanged {
                position += $0.translation.height
                if position < 0 { position = 0 }
            }
            .updating($isDragging) { (value, state, transaction) in state = true })
    }
}

Any thoughts on how to diagnose or fix that?