HarmonyOS 鸿蒙Next DevEco Studio 升级到3.1beta后数组对象无法获取数据了？

HarmonyOS 鸿蒙Next DevEco Studio 升级到3.1beta后数组对象无法获取数据了？

升级到3.1beta后原有的数组赋值功能无效了？？

//遍历也不能给数组赋值----------------------------------------------------------------------

@State pitchDataArray: Array<PitchData> = []; 

this.pitchModel = JSON.parse(data.result + "");
this.pitchDataArray = this.pitchModel.data;//升级前可以直接给数组对象赋值。升级后this.pitchDataArray数组始终是0条数据

//遍历也不能给数组赋值----------------------------------------------------------------------

for (let index = 0; index < this.pitchModel.data.length; index++) {
    const element = this.pitchModel.data[index];
    this.pitchDataArray.push(element);//这里循环遍历后数组任然是0条？
}

不晓得什么原因，望指点