Bug Type: Component

Environment

• Vue Version: 3.3.4
• Element Plus Version: 2.3.8
• Browser / OS: Chrome 114.0.5735.198 / Linux Mint 20.3 Cinnamon
• Build Tool: Vite

Reproduction

Related Component

• el-scrollbar

Reproduction Link

Github Repo

Steps to reproduce

1. Build in prod mode (npm run build) (PROD mode is important, because in dev mode works fine)
2. Open builded project
3. Click by add button
4. See in console. You see TypeError: Cannot read properties of null (reading 'insertBefore')

What is Expected?

Work indent (without errors)

What is actually happening?

TypeError: Cannot read properties of null (reading 'insertBefore')

Additional comments

I created environment in element-plus-playground, but this bug not reproduce, because element-plus-playground build project in dev mode.
Please, see link with github.

I see next behavior, in TestComp.vue we have

<template v-if="visibleTitle" #title>
  <h1>My title</h1>
</template>

If you change this to:

<template #title>
  <h1 v-if="visibleTitle">My title</h1>
</template>

Or you comment <el-scrollbar> in TestItems.vue

Everything will work. This is strange.