This happens to me as well when is used template tag inside root template tag, just like this

<template>
<div class="demo">
  <template v-if="cond">
    <h1>Hello world</h1>
  </template>
  <template v-else>
    <h1>No Hello world</h1>
  </template>
</div>
<template>

This happens to me as well when is used template tag inside root template tag, just like this

<template>
<div class="demo">
  <template v-if="cond">
    <h1>Hello world</h1>
  </template>
  <template v-else>
    <h1>No Hello world</h1>
  </template>
</div>
<template>