自定义指令v-auth当作用在el-dropdown-item上时失效

[PathfinderAx]

  <template #tableHeader>
    <el-button v-auth="'add'" type="primary" @click="openAmdDialog('新增')">新增</el-button>
    <el-dropdown>
      <el-button type="primary">
        导出<el-icon class="el-icon--right"><arrow-down /></el-icon>
      </el-button>
      <template #dropdown>
        <el-dropdown-menu>
          <el-dropdown-item v-auth="'exportTxt'">导出为TXT</el-dropdown-item>
          <el-dropdown-item v-auth="'exportExcel'">导出为Excel</el-dropdown-item>
        </el-dropdown-menu>
      </template>
    </el-dropdown>
  </template>

如图，在上方代码中使用el-dropdown组件时，当自定义指令v-auth当作用在el-dropdown-item上时失效，还是会全部展示，且控制台会报出警告