HarmonyOS 页面重载问题

使用Observed和ObjectLink的时候出现了问题，代码如下：实体类：

@Observed
export class BannerBean {
  public desc?: string;
  public id?: number;
  public imagePath?: string;
  public isVisible?: number;
  public order?: number;
  public title?: string;
  public type?: number;
  public url?: string;
  public itemBean?: BannerItem

  constructor(desc?: string, id?: number, imagePath?: string, isVisible?: number,
    order?: number, title?: string, type?: number, url?: string,itemBean?: BannerItem) {
    if (desc){
      this.desc = desc;
    }
    if (id){
      this.id = id;
    }
    if (imagePath) {
      this.imagePath = imagePath;
    }
    if (isVisible) {
      this.isVisible = isVisible;
    }
    if (order) {
      this.order = order;
    }
    if (title){
      this.title = title;
    }
    if (type) {
      this.type = type;
    }
    if (url) {
      this.url = url;
    }
    if (itemBean) {
      this.itemBean
    }
  }
}

@Observed
export class BannerItem {
  public name?:string

  constructor(name?: string) {
    if (name) {
      this.name = name
    }
  }
}
viewModel：
export class HomeViewModel {

  public bannerList: Array<BannerBean> = []

  constructor() {
  }

  public getBanner(page:number) {
    WanAndroidService.getBanner().then((res)=>{
      if (res) {
        if (page == 1) {
          this.bannerList = res
        } else {
          res.forEach((item)=>{
            this.bannerList.push(item)
          })
        }
        console.error(`请求结果:${this.bannerList.length}`)
      }
    })
  }

  public updateItemTitle(currentIndex:number) {
    console.error(`进入事件:${currentIndex}`)
    let tempList = this.bannerList
    tempList.forEach((item,index)=>{
      if (index == currentIndex) {
        tempList[index].title = `${item.title}更新的数据`
        tempList[index].itemBean = new BannerItem("张三")
      }
    })
    this.bannerList = []
    this.bannerList = tempList
    console.error(`事件结果:${JSON.stringify(this.bannerList[currentIndex])}`)
  }
}

UI显示：

@Entry
@Component
struct Index {
  @State viewModel: HomeViewModel = new HomeViewModel()
  @State currentPage: number = 0
  
  build() {
    Column() {
      Text('获取数据')
        .fontSize(50)
        .onClick(()=>{
          this.currentPage = this.currentPage + 1
          this.viewModel.getBanner(this.currentPage)
        })
        .fontWeight(FontWeight.Bold)
      if (this.viewModel.bannerList.length != 0){
        DemoList({
          viewModel: this.viewModel,
          list: this.viewModel.bannerList
        })
      }
    }
    .height('100%')
    .width('100%')
  }
}

@Component
export struct DemoList {
  @Link viewModel: HomeViewModel
  @State list:Array<BannerBean> = []
  build() {
    Column(){
      ForEach(
        this.list,
        (item: BannerBean,index: number) => {
          DemoItem({
            item: item,
            onItemClick: () => {
              this.viewModel.updateItemTitle(index)
            }
          })
        }
      )
    }
  }
}
@Component
export struct DemoItem {
  @ObjectLink item: BannerBean;
  onItemClick: () => void = () => {}

  build() {
    Column(){
      Text(this.item.title)
        .fontColor(Color.Black)
      if (this.item.itemBean && this.item.itemBean.name) {
        Text(this.item.itemBean.name)
          .fontColor(Color.Black)
      }
    }
    .onClick(()=>{
      this.onItemClick()
    })
    .height(50)
    .backgroundColor(Color.Red)
    .margin({bottom: 20})
  }
}

在updateItemTitle中改变对应item的值时不会引发页面刷新，同时在page不为1时往数据中push数据，也没有出现在页面上，这是为什么？