What Is This Issue?
After OTTO applies an H1 optimization to your page, you may notice a brief visual glitch where the original H1 appears for a split second before switching to the optimized version. This is called a Flash of Original Content (FOOC) and is a rendering or cache issue — not a sign that OTTO's optimization has failed.
Common symptoms include:
- The H1 visibly changes text a moment after the page finishes loading
- The H1 shown in your browser differs from what appears in the page source
- The issue appears intermittently, often after a recent OTTO update
- Visitors or site audits see two different H1 values depending on timing
This behavior is almost always caused by a stale cache — either in Webflow, your browser, or a CDN layer — serving the old H1 while OTTO's JavaScript update is still executing on top of it.
Why This Happens
OTTO injects optimizations at runtime using a JavaScript snippet embedded on your site. When a visitor loads your page, the browser first renders the cached HTML (which may contain the old H1), and then OTTO's script executes and replaces the H1 with the optimized version. If the cache is stale, the gap between the initial render and the script execution becomes visible.
The most common sources of a stale cache are:
- Webflow's internal cache — Webflow caches published pages. If you have not republished your site since OTTO's last update, the old page HTML may still be served.
- Browser cache — Your browser stores a local copy of the page. Returning visitors are especially likely to see the old version.
- CDN or proxy cache — If your site sits behind a CDN or reverse proxy, those edge nodes may be serving a cached version that predates OTTO's changes.
Step-by-Step Fix
Work through the steps below in order. Most customers resolve the issue at Step 1 or Step 2.
- Verify OTTO's H1 optimization is active. Log in to your Search Atlas account and confirm that OTTO is deployed on the affected site and that H1 optimization has been applied. If it has not been deployed, deploy OTTO and allow a few minutes for changes to propagate before testing.
- Republish your Webflow site. Republish your site to your live domain. This forces Webflow to regenerate the cached page HTML with the latest content. After publishing, wait 2–3 minutes before testing.
- Clear your browser cache. Use your browser's settings to clear cached images and files, then do a hard reload of the page to confirm the updated H1 is displayed correctly.
- Purge any CDN or proxy cache. If your site is served through a CDN or reverse proxy, purge the cache for the affected pages through that service's dashboard so the updated HTML is fetched from origin.
If you have completed all steps above and the FOOC persists, the issue may require a review of how OTTO's script is loading relative to your page's render pipeline. Please have the affected page URL and a description of the behavior ready when you reach out.
If you need further assistance, open the chat widget in the bottom-right corner of the platform and type human teammate to be connected with a member of our team.