Stored result of json decode is suddenly gone/ Observed Object doesn't react in WatchOS

Question

I decode json data from an iPhone to a watch and store it into an object (custom class: PeopleObj) which is declared as @ObservableObject. However, the contenview containing this object doesn't get the data

This is the data model:

struct Person: Codable {
    var pid : UUID
    var dept: String
    var name: String

    init(pid: UUID, dept: String, name: String){
        self.pid = pid
        self.dept = dept
        self.name = name
    }
}
    
class PeopleObj: ObservableObject, Identifiable , Codable{
    @Published var people: [Person] = []
        
    // get codable
    init() { }
    
    enum CodingKeys: CodingKey {
        case people
    }
    
    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(people, forKey: .people)
        
    }
    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        people = try container.decode(Array.self, forKey: .people)
    }
}

Following is the decode part at WatchOS, here I get the json data as a reply on a request and decode it into the peopleObj:

let jsonEncoder = JSONEncoder()
do {
    let jsonDataRequest = try jsonEncoder.encode(request)
    print("send request")
    self.session?.sendMessageData(jsonDataRequest, replyHandler: { response in
        print(">>>>>>>>>>>>>>>>> DATA-Reply vom iPhone received: \(response)")
        DispatchQueue.main.async {
            let jsonDecoder = JSONDecoder()
            do {
                self.peopleObj = try jsonDecoder.decode(PeopleObj.self, from: response)
                for person in self.peopleObj.people {
                    print("received person: \(person.name), dept \(person.dept)")
                    // here it prints correctly
                }
                                
            } // End do decode
            catch { print("decode catch!!!!!!!")  }
        } // Dispatch main
    },
    errorHandler: { error in
        print("Error sending message: %@", error)
    }) // sendMessageData
} // End do decode
catch { print("encode catch!!!!!!!")  }

This is the contenview, observing the object:

struct ContentView: View {
        
    @ObservedObject var peopleObj: PeopleObj
        
    var body: some View {
     
        VStack {
            List(peopleObj.people, id: \.pid) { person in
                HStack {
                    Text("name: \(person.name)")
                    Spacer()
                    Text("dept: \(person.dept)")
                }
            }
        }
    }
}

I tried decoding the json into a struct and then manualy add the values to the peopleObj - that works but doesn't seem to be the correct process to me! I can't explain why, guess it has something to do with value vs referencing.

Any help and or idea is more than welcome!!!!!

Edit: The peopleObj is defined in the HostingController:

    class HostingController: WKHostingController<ContentView> , WCSessionDelegate{
   
   @ObservedObject var peopleObj:PeopleObj = PeopleObj()

The ContentView is called from the HostingController

 override var body: ContentView {
     return ContentView(peopleObj: peopleObj)
}