弹框内a-form表单校验按钮loading属性失效原因

功能：a-modal内提交表单给button加loading属性，避免多次重复提交

以下错误写法导致loading属性失效

<a-modal v-model:open="open" title="Title" :confirm-loading="confirmLoading" @ok="handleOk">
    <p>{{ modalText }}</p>
    <template #footer>
      <a-button key="back" @click="handleClose">取消</a-button>
      <a-button key="submit" type="primary" :loading="loading" @click="save">确定</a-button>
    </template>
</a-modal>
    
  const save = () => {
	formRef.value.validate()
	.then(() => {
		loading.value = true
		api().then(()=>{
			...
		}).finally(()=>loading.value = false)
	})	

正确写法，需要加上异步

  const save = () => {
	formRef.value.validate()
	.then(() => {
		setTimeout(() => {
			loading.value = true
			api().then(()=>{
				...
			}).finally(()=>loading.value = false)
		})
	})	

官方文档说明