Why is Google appending a different website's brand name to the end of SERP title?

[Ria_]

I've recently been shown some SERP results where Google is appending a different website's brand name to the end of the SERP title. It's actually rewriting the brand's name to that of the other website. (This is obviously not ideal.) Why would this be?

The other website doesn't even stock the same product, so there shouldn't be any confusion there. But even if it did, many websites stock the same products. Just confusing...

[MarieHaynes]

That's a tough one. If you want to DM me the url (or email it to me at marie at marie haynes dot com) I'd be happy to take a quick look.

[Ria_]

Hi Marie. Thanks for your response.

I'm a bit hesitant to share the examples for my client's privacy. I hope you understand. I do not work on these websites' SEO, I was only asked to look into it to see if I can spot anything that could be causing this. I do, however, work for a larger website that owns both the websites, so that's why I've been asked.

The two businesses share the same address. I was thinking that this may be a factor, but neither site has a Google My Business listing or much in the way of offsite citations. No DMOZ listings.

There are no external canonicals in place, and no mention of the others' URL on the respective sites. Double checked

No duplicate content as both sites sell different products with no overlap, so no duplicate product listings or content. The two sites are not even competing in SERPs for any similar keywords.

[MarieHaynes]

This is an unusual question. Any chance you could share the example with us?

Do the two websites have much duplicate content between them? Google may be applying a canonical if they think it is duplicate content. Any chance that a canonical was inadvertently placed by you? (I know that's probably pretty unlikely.)

Any chance this has something to do with the businesses' DMOZ listing?