onAppear not getting called in List all the time in iOS 16. works fine in iOS 15

onAppear is strangely not getting called for row which are visible later. Im downloading the image in on Appear and then setting it.

List {
  ForEach(0..<(viewModel.rows.count), id: \.self) { index in
    if let imageModel = viewModel.getImageModel(index: index) {
      SomeCustomView(imageModel)
        .onAppear {
          if imageModel.image == nil {
            imageModell.loadAdBanner()
          }
        }
    }
    if #available(iOS 15.0, *) {
      VStack(spacing: 0) {
        VStack(alignment: .leading, spacing: 16) {
          HStack(spacing: 0) {
            HeaderView(viewModel:
                                      TitleViewModel(headerTitle: viewModel.rows[index].headerTitle))
            Spacer()
            TitleView(viewModel: TitleViewModel(row: viewModel.rows[index]))
          }
          .frame(height: 36)
          .padding(.horizontal, 16)
          .shimmering(active: viewModel.showShimmer)
          .background(viewModel.showShimmer ? .colorDCDCDC : Color.clear)
          CategoriesList(l1Category: viewModel.categories[index],
                         categories: viewModel.categories[index].subcategories,
                         showShimmer: viewModel.showShimmer)
        }
        .padding(.bottom, 16)
      }
      .listRowSeparator(.hidden)
      .frame(maxWidth: .infinity) // Make the row take up full width
      .listRowInsets(EdgeInsets()) // Remove row insets
      .padding(0)
  } else {
 sameCode without listSepeartor(.hidden) 

}