Previewing edits to existing pages causes an error

[wrenaria]

When I try to preview changes to pages on the library website via the editor, it throws a "critical error." It seems to only happen when trying to preview drafts of existing pages, it doesn't do when if I start a new page and then try to preview it.

---

[spelkey-ucd]

Bug introduced when upgraded to php8.

It's an issue with Timber, that will be patched in their next release.