SwiftUI warning for "Publishing changes from within view updates" on macOS

I have a simple example of a List with multiple selection. When I run it on macOS, and select an item from the list, it works fine but I get a warning in the console:

Publishing changes from within view updates is not allowed, this will cause undefined behavior

Interestingly, it doesn't produce a purple 'issue' in the Issues navigator, but as I change selection, I keep getting this warning.

Also, the warning doesn't show when running the same code on iOS.

Here is code to reproduce it:

struct TestListSelection: View {
    
    let testArray = [TestItem(itemValue: 1), TestItem(itemValue: 2), TestItem(itemValue: 3), TestItem(itemValue: 4)]

    @ObservedObject var listOptions: TestListViewModel
    
    var body: some View {
        List (selection: $listOptions.multipleSelection) {
            Section("Header") {
                ForEach (testArray, id: \.self) { item in
                    Button {
                        print("row tapped - \(item.itemValue)")
                    } label: {
                        VStack {
                            HStack {
                                Text(item.itemString)
                            }
                        }
                        
                    }
                    .buttonStyle(.plain)
                }
            }
        }
        .listStyle(.plain)
    }
}

public struct TestItem: Identifiable, Hashable {
    public let id = UUID()
    let itemValue: Int
    
    var itemString: String {
        get {
            return "test \(itemValue)"
        }
    }
}

@MainActor
public class TestListViewModel: NSObject, ObservableObject {
    @Published public var multipleSelection = Set<TestItem>()
}

I annotated the view model with @MainActor as suggested in other threads, but it doesn't silence the warning.

If I move the multipleSelection into the view itself, and make it a @State variable (bypassing the viewModel completely), it works and doesn't produce a warning. But I need it work so I can pass in selection from the UIKit part of the app as well. I also can't migrate to @Observable because my main project has to support iOS15 and above.

Any clue why this is happening on macOS specifically, and what I can do to avoid it?