I don't use Sublime Text (so can't check the new branch), but this issue appears on GitHub which uses this repository for syntax highlighting and is using the latest version of the master branch.

The optional chaining operator (?.) causes the file to stop syntax highlighting the rest of the file when it is used in an attribute inside <template>

With optional chaining operator:

<script setup lang="ts">
  const hello = {}
</script>
<template>
	<div v-if="hello?.world" />
</template>
<style>
	div {
      font-size: 16px;
    }
</style>

Without optional chaining operator:

<script setup lang="ts">
  const hello = {}
</script>
<template>
	<div v-if="hello.world" />
</template>
<style>
	div {
      font-size: 16px;
    }
</style>