写前端日期选择的时候遇到一个很奇怪的问题，回显赋值后再次修改无法更新数据

<div>
          <el-form-item label="选择时间："
                        prop="bxrq"
                        class="searchtime30">
            <el-date-picker v-model.trim="searchParam.bxrq"
                            type="daterange"
                            start-placeholder="开始日期"
                            range-separator="至"
                            end-placeholder="结束日期"
                            value-format="yyyy-MM-dd"
                            :picker-options="pickerOptions1"
                            @blur="changePackageTime"
                            clearable>
            </el-date-picker>
          </el-form-item>
        </div>

回显时 //用这个方法赋值

  let riqi=[sstj.startTime,sstj.endTime] // [ "2022-11-01", "2022-11-17" ] 
  this.$set(this.searchParam,'bxrq',riqi)