One bad import killed reviews on 4,000 pages

One bad import killed reviews on 4,000 pages

A SaaS review platform noticed their pages stopped showing review snippets in search — the star ratings vanished from results across thousands of URLs. No deploy was blamed; everything looked fine in the browser.

In the browser, it was fine. So we rendered with a strict, older JavaScript engine closer to Google's renderer at the time. The console lit up: a single component threw on an optional-chaining syntax their build hadn't transpiled for the older engine.

That component rendered the structured-data script block with the review schema. When it threw, React's error boundary caught it and rendered nothing in its place — silently, in production, only on engines that didn't support that syntax. Modern user browsers were unaffected. Google's renderer wasn't.

The rendered DOM Google captured had no review schema. The rich results dependency on that JSON-LD evaporated.

A single un-transpiled feature can knock out structured data for an entire site, and it leaves zero trace in your own browser.

Fix: corrected the build target, moved JSON-LD to server-rendered output independent of React.

Result: review rich results returned within two weeks, CTR on the affected pages +41%.