I also encounter this problem, have you solved it?

get the input element when you click, and add the focus () event

Array.from ('el-select')). ForEach ((item) = > {

  item.children[0].children[0].removeAttribute('readOnly')
  item.children[0].children[0].onblur = function () {
    let _this = this
    setTimeout(() => {
      _this.removeAttribute('readOnly')
    }, 200)
  }
})