SwiftUI - View disappears if animated

I have asked this question on stack overflow. You may read it there, because I have included 2 GIFs that illustrates the problem.

Code Block 
struct SegmentedControl: View {
		private var items: [String] = ["One", "Two", "Three"]
		
		@Namespace var animation:Namespace.ID
		
		@State var selected: String = "One"
		var body: some View {
				ScrollView(.horizontal) {
						HStack {
								ForEach(items, id: \.self) { item in
										Button(action: {
												withAnimation(.spring()){
														self.selected = item
												}
										}) {
												Text(item)
														.font(Font.subheadline.weight(.medium))
														.foregroundColor(selected == item ? .white : .accentColor)
														.padding(.horizontal, 25)
														.padding(.vertical, 10)
														.background(zStack(item: item))
										}
										
								}
						} .padding()
				}
		}
		
		private func zStack(item: String) -> some View {
				ZStack{
						if selected == item {
								Color.accentColor
										.clipShape(Capsule())
										.matchedGeometryEffect(id: "Tab", in: animation)
						} else {
								Color(.gray)
										.clipShape(Capsule())
						}}
		}
}