I spotted a thread on Reddit that seemed off from an SEO perspective. A site owner said he switched to a new domain four months ago, Google indexed and served the new domain but then all of a sudden, Google started to show the old domain again four months after the migration.

I don't know all the details, outside of what is in the Reddit thread. In summary, here is what this person wrote:

• Domain Migration: The author changed their website's name and domain at the beginning of 2026 to cover an additional topic.
• Successful Transition: They correctly implemented redirects and the Google Change of Address tool. By April, traffic had recovered, and the new domain was successfully indexed, receiving about 5,000 impressions per day.
• Sudden Reversion: Four months later, Google unexpectedly de-indexed over 5,000 pages on the new site (categorizing them as "Crawled, currently not indexed"), causing impressions on the new domain to drop to just 20 per week.
• Old Domain Re-indexed: At the same time, Google completely re-indexed the old domain, and all search impressions and clicks are now showing up there in Google Search Console.

John Mueller from Google did respond, asking the user to direct message him. He also added that:

(1) "Sometimes things just take a particularly long time to be fully processed," he wrote.

(2) And that he should make sure to do the change of address change for both the www and non-www version. He wrote, "One thing which we noticed (and adjusted in the documentation a while back) that can help is to make sure that you have change of address set up in search console for both www and non-www , so that it can fully migrate the domain."

I can't imagine it is number two, right? I mean, we do know when you specifically search for the old domain, Google will likely show it. But that can't be it too, right?

What do you think?

Forum discussion at Reddit.

Maybe there is an issue on Google's end. I also have been getting emails about site migrations going wrong, months and months later. So have Glenn Gabe and Marie Haynes:

I'm seeing the same as Glenn re site migrations gone wrong.

I have a theory. I think a site migration triggers a new quality assessment. And I think Google is getting more strict about what it indexes now.

They keep telling us about the importance of original, insightful content that demonstrates some element of talent or skill and genuine effort.

Often GSC for these sites with migrations gone wrong shows all the pages in crawled-not currently indexed.

So Google is seeing the pages and choosing not to index them.

And in most cases these are decent sites but the content offers nothing original compared to what is currently indexed.

— Marie Haynes (@Marie_Haynes) October 13, 2026