HarmonyOS 鸿蒙Next中为什么状态变量不更新？isShow1和isShow2都可以更新，但是isShow3状态变量不更新

HarmonyOS 鸿蒙Next中为什么状态变量不更新？isShow1和isShow2都可以更新，但是isShow3状态变量不更新

isShowModel.ets

@ObservedV2
export class IsShowModel {
  @Trace
  isShow: boolean = false
  static instance?: IsShowModel
  static instance2: IsShowModel = new IsShowModel()

  static getInstance() {
    if(!IsShowModel.instance) {
      return new IsShowModel()
    }
    return IsShowModel.instance
  }

  getInstance2() {
    if(!IsShowModel.instance) {
      return new IsShowModel()
    }
    return IsShowModel.instance
  }
}

Index.ets

import { IsShowModel } from '../models/isShowModel'

@Entry
@ComponentV2
struct Index {
  @Local isShow1: IsShowModel = new IsShowModel()
  @Local isShow2: IsShowModel = IsShowModel.getInstance()
  @Local isShow3: IsShowModel = IsShowModel.instance2.getInstance2()

  build() {
    Column({space: 22}) {
      Column({space: 38}) {
        if(this.isShow1.isShow) {
          Text('Hello World!!!')
            .width(150)
            .height(150)
            .backgroundColor(Color.Pink)
        }
        Button("点我修改isShow1")
          .onClick(() => {
            this.isShow1.isShow = !this.isShow1.isShow
          })
      }

      Column({space: 38}) {
        if(this.isShow2.isShow) {
          Text('Hello World!!!')
            .width(150)
            .height(150)
            .backgroundColor(Color.Pink)
        }
        Button("点我修改isShow2")
          .onClick(() => {
            this.isShow2.isShow = !this.isShow2.isShow
          })
      }

      Column({space: 38}) {
        if(this.isShow3.isShow) {
          Text('Hello World!!!')
            .width(150)
            .height(150)
            .backgroundColor(Color.Pink)
        }
        Button("点我修改isShow3")
          .onClick(() => {
            this.isShow3.isShow = !this.isShow3.isShow
          })
      }
    }
    .width('100%')
    .height('100%')
  }
}