site: operator showing old URLs still being indexed

[Calockwoody]

Hoping someone can point me in the right direction here, been looking into it quite a bit.

Our site is an eCommerce site, 12 months ago our company had 7 different domains, all with different product categories on, for example:

www.productcat1.com

www.productcat2.com

About 12 months ago all these domains got merged onto www.brandname.com. However, when searching for site:www.productcat1.com in Google there are a lot of pages still being indexed, some of the URLs displayed never existed on the product category sites and refer to content or products added only after the merge (confusing).

Just to confirm, these are the steps already taken; all old domains have been 301 redirected to www.brandname.com, there has been a search console change of address for each and there is nothing currently hosted anywhere referring to www.productcat1.com etc

I have also checked all backlinks pointing towards these domains and there are a few still that I can't change however they aren't to URLs displayed as still being indexed by Google.

[phranque]

However, when searching for site:www.productcat1.com in Google there are a lot of pages still being indexed, some of the URLs displayed never existed on the product category sites and refer to content or products added only after the merge (confusing).

i would use a header checker tool on some of those urls and make sure the entire response chain (status code and response headers) all looks correct.
i would also use "fetch as googlebot" in GSC on these urls and see if that shows anything.

[Calockwoody]

Ok, thanks for the reply, I just double checked both of these and they only confirm that the 301 redirect is working as intended. Nothing unusual is showing up.

[tangor]

Do all the original domains still exist? (Should for redirects to work properly). If they do, might be seeing confusion at the SE level and, of course, their continual attempts to check any URL they have met.