SwiftUI: View is not rendered properly

Problem: When clicking on an item, it will be (un-)completed. When it's completed then ChildView should show GroupsView. However, that's not the case.

The logs are like this:

init, group Fruits - items not completed false - showItems false
body, group Fruits - items not completed false - showItems true
init, group Fruits - items not completed false - showItems false
init, group Fruits - items not completed false - showItems false

import SwiftUI
import SwiftData

@main
struct MainApp: App {
    var body: some Scene {
        WindowGroup {
            SomeView()
        }
        .modelContainer(appContainer)
    }
}

struct SomeView: View {
    @Query private var items: [AItem]
    
    var body: some View {
        ParentView(items: items)
        
    }
}

struct ParentView: View {
    private var groupedItems: [GroupedAItems] = []
    
    init(items: [AItem]) {
        Dictionary(grouping: items) { $0.categoryName }
            .forEach {
                let groupedItems = GroupedAItems(categoryName: $0.key, items: $0.value)
                self.groupedItems.append(groupedItems)
            }
    }
    
    var body: some View {
        ScrollView {
            VStack(spacing: 15) {
                ForEach(groupedItems, id: \.self.categoryName) { groupedItems in
                    ChildView(groupedItems)
                }
            }
        }
    }
}

struct ChildView: View {
    public var groupedItems: GroupedAItems
    @State private var showItems: Bool
    
    init(_ groupedItems: GroupedAItems) {
        self.groupedItems = groupedItems
        self._showItems = State(initialValue: !groupedItems.completed)
        print("init, group \(groupedItems.categoryName) - items not completed \(!groupedItems.completed) - showItems \(showItems)")
    }
    
    var body: some View {
        print("body, group \(groupedItems.categoryName) - items not completed \(!groupedItems.completed) - showItems \(showItems)")
        if showItems {
            return AnyView(ItemsSampleView(items: groupedItems.items, onClick: { showItems = false }))
        } else {
            return AnyView(GroupsView(groupedItems: groupedItems, onClick: { showItems = true }))
        }
    }
}

struct ItemsSampleView: View {
    public var items: [AItem]
    public var onClick: () -> Void
    
    private let gridColumns = [GridItem(.adaptive(minimum: CGFloat(70)))]
    
    var body: some View {
        VStack {
            Button {
                onClick()
            } label: {
                Image(systemName: "chevron.down")
            }
            
            Spacer()
            
            LazyVGrid(columns: gridColumns) {
                ForEach(items.sorted(by: {$0.name < $1.name})) { item in
                    Button {
                        item.completed.toggle()
                    } label: {
                        Text(item.name)
                    }
                }
            }
        }
    }
}

struct GroupsView: View {
    public var groupedItems: GroupedAItems
    public var onClick: () -> Void
    
    var body: some View {
        VStack {
            Button {
                onClick()
            } label: {
                Image(systemName: "chevron.down")
            }
            
            Spacer()
            
            Text(groupedItems.categoryName)
        }
    }
}

@Model
final class AItem: Identifiable {
    @Attribute(.unique) public var id: String
    public var name: String
    public var categoryName: String
    public var completed = false
    
    internal init(name: String, categoryName: String) {
        self.id = UUID().uuidString
        self.name = name
        self.categoryName = categoryName
    }
}

struct GroupedAItems {
    var categoryName: String
    var items: [AItem]
    var completed: Bool {
        items.filter { !$0.completed }.isEmpty
    }
}

@MainActor
let appContainer: ModelContainer = {
    do {
        let container = try ModelContainer(for: AItem.self)
        
        // Make sure the persistent store is empty. If it's not, return the non-empty container.
        var itemFetchDescriptor = FetchDescriptor<AItem>()
        itemFetchDescriptor.fetchLimit = 1
        
        guard try container.mainContext.fetch(itemFetchDescriptor).count == 0 else { return container }
        
        container.mainContext.insert(AItem(name: "Apple", categoryName: "Fruits"))
        
        return container
    } catch {
        fatalError("Failed to create container")
    }
}()