Starting a website?

Purpose-Built Templates

ZU2B Blueprints

Business in a Box

Reference

ZU2B Pulse™

See what visitors experience before they leave — paste any public URL and get a plain-English performance report in seconds.

Scan Your URL Free
FAQ • Support

WordPress FSE 404 Template Overridden by Full Site Editor Custom HTML Blocks

Field Note #169
🔬 Resolved 🟢 Beginner ⏱ 30 Minutes ✓ Observation from Experience

⚡ Quick Fix (TL;DR)

The Fix: Open Appearance → Editor → Templates → 404 → locate and delete the Custom HTML blocks containing the old content → add the new branded content as a fresh Custom HTML block → Save.

Was this helpful? Thanks for the feedback!
Observed:
Editing the template-404.php pattern file in a theme didn’t change what displayed on 404 pages. The old About Us content kept appearing.

Confirmed cause:
The WordPress Full Site Editor had Custom HTML blocks embedded directly in the 404 template that overrode the pattern file entirely. The FSE template takes precedence over the PHP pattern file when both exist.

Resolution:
Open Appearance → Editor → Templates → 404 → locate and delete the Custom HTML blocks containing the old content → add the new branded content as a fresh Custom HTML block → Save.

Generalized lesson:
In FSE themes, the visual template editor takes precedence over pattern PHP files. If editing a pattern file has no visible effect, check whether the FSE template for that page type has blocks that override it.

Tagged in :

More from the field