小程序体验版无法正常运行，报错is not a function？

开发工具、真机调式模式下能正常运行，上传体验版在手机上无法运行。。出现如下报错。。

a._request is not a function;at "pages/acct/acct" page lifeCycleMethod onLoad function TypeError: a._request is not a function at be._GetTermListToDownMenu (app-service.js:5892:1763) at be.onLoad (app-service.js:5892:2468) at be.<anonymous> (WASubContext.js:1:1446679) at be.p.__callPageLifeTime__ (WASubContext.js:1:1446424) at Tt (WASubContext.js:1:1461733) at at (WASubContext.js:1:1464743) at At (WASubContext.js:1:1464810) at Function.<anonymous> (WASubContext.js:1:1469093) at i.<anonymous> (WASubContext.js:1:1437956) at i.emit (WASubContext.js:1:446330)

页面JS代码：

onLoad: function () {

var t = this

    t.setData({ overlay_show: true })

    t._GetTermListToDownMenu().then((e) => {

      if (e.data.length > ) {

        t.setData({

          term_opt: e.data

        })

      }

      wx.hideLoading()

      t.setData({ overlay_show: false })

    })

},_GetTermListToDownMenu:function(){

    var t = this

    var _data = { code: 123,abc:987}

    return app._request(_data, app.globalData._GetTermApi,'');

  }