element-plus：el-upload上传文件只能一次，第二次失效

<template>
  <el-upload
    ref="upload"
    :limit="1"
    :on-exceed="handleExceed"
    :auto-upload="false"
  >
  </el-upload>
</template>
<script setup lang="ts">
import { ref } from 'vue'
import { genFileId } from 'element-plus'
import type { UploadInstance, UploadProps, UploadRawFile } from 'element-plus'
const upload = ref<UploadInstance>()
const handleExceed: UploadProps['onExceed'] = (files) => {
  upload.value!.clearFiles()
  const file = files[0] as UploadRawFile
  file.uid = genFileId()
  upload.value!.handleStart(file)
}
const submitUpload = () => {
  upload.value!.submit()
}
</script>