SwiftUI Nested Publishing

Question

@MainActor
final class VM : ObservableObject {

 @Published var secondClass: secondClass
 @Published var counter: Int = 0

init(secondClass: secondClass) {
    self.secondClass = secondClass
}
}


class secondClass: ObservableObject {
    @Published var number : Int = 0
    @Published var users : [DBUser]
    @Published var userCount : Int

init(users: [DBUser], userCount: Int) {
    self.users = users
    self.userCount = userCount

}
}

struct test2: View {
@ObservedObject var VM : VM
var body: some View {

    VStack{
        Text("\(VM.secondClass.userCount)")

        Button {

            DispatchQueue.main.async {
                VM.secondClass.userCount =  1
                //VM.counter += 1
            }
           
         
        } label: {
            Text("Click Here")
        }
        
    }
}

}

I have a nested class inside my ViewModel but when I update the classes attributes it doesn't cause the publisher to fire, whereas if I update a value directly attached to the ViewModel it does fire. How do I make the publisher fire when I update one of the nested classes attributes? Thanks