Did you know that returning a "results not found" type of page can result in Google Search considering that page a soft 404 and thus removing it from the search results? We know Google recently changed how it determines some soft 404 pages, but this tidbit is not new to that change.
In both a Google Webmaster Help thread and a Twitter thread, there are examples of Google spiking in showing soft 404s for pages with messages like - no results found or similar language used on that page. Then when you remove that message, the soft 404 response goes away.
John Mueller said on Twitter that those responses "could certainly throw us off." John added "It's less obvious here, but a similar case we've seen is when a page is served with a noindex, and client-side JavaScript removes that."
Here is a tweet showing the soft 404 spike:
Google's Soft 404 bug is back @JohnMu @searchliaison? I'm seeing huge spike across multiple domains. Unique pages disappear, URL inspection tool is hit or miss "Something went wrong. If the issue persists, try again in a few hours". Was this resolved completely for you @jsilton? pic.twitter.com/qmJMTJJ3XF
— Tom Rothwell (@trothwell_null) June 30, 2021
John then being asked about if this can be the case:
That could certainly throw us off.
— 🍌 John 🍌 (@JohnMu) July 9, 2021
It's less obvious here, but a similar case we've seen is when a page is served with a noindex, and client-side JavaScript removes that.
And then making a change on the site to reduce the soft 404s and improve the indexing:
Thanks again, Tom! We made the changes to the 'swiftsearch' container and have seen improvements 🙏 pic.twitter.com/VlEGcGvEw2
— George Aston (@GeorgeSAston) July 19, 2021
This is a similar story in the Google Webmaster Help.
In any event, just keep this in mind and it obviously makes sense. But spotting this can be hard for a webmaster.
Forum discussion at Google Webmaster Help and Twitter.