Steps to replicate the issue (include links if applicable):
On a wiki running PHP 8.0 or newer, attempt to edit a talk page with the 2017 wikitext editor using the "Add topic" entrypoint.
Under the hood, this makes an API call like https://www.mediawiki.org/w/api.php?action=visualeditor&format=json&paction=wikitext&page=User_talk%3ATK-999&uselang=en&formatversion=2§ion=new, which under the hood calls the equivalent of https://www.mediawiki.org/w/api.php?action=query&prop=revisions&revids=2471355&rvslots=main&rvsection=new&rvprop=content|ids.
What happens?:
Observe an error like There is no section new in revision 422.
What should have happened instead?:
The editor should have initialized with appropriate content.
Software version: 1.37