CSS selector :not() no longer matches

[Fd929c2CE5fA]

Describe the bug

See reproduction below

Possibly relevant changes:

• breaking: scope :not(...) selectors #13568

Reproduction

5.1.3

5.0.0-next.265

Logs

No response

System Info

N/A

Severity

blocking an upgrade

[paoloricciuti]

Mmm the issue seems to be that the svelte class is not added to the other docs

var root = $.template(`<div class="a svelte-ys7f0i">aaa</div> <div>bbb</div> <div>ccc</div>`, 1);

So the generated css is actually correct, is the template that is not