Happens all the time. I see it especially with authors who have a lot of books. For instance, I just looked at Barbara Delinsky's listing, and on page 3, five titles are by other authors, three of them published (as Delinsky is) by a big publisher. The other two are in KU.
I noticed when I followed your link that page 1 was all your books but page 2 had five books not by you and none of them said Sponsored.
I find this surprising because usually an author's titles are interrupted by Sponsored ads all over the place. Top, in between, bottom, what have you. My own two little pages have no such interruptions, but the very last listing is a public domain title that someone has copied from Project Gutenberg and has the audacity to be selling.
I'll be interested to hear Amazon's response, because it seems to me that showing other people's books when your name is searched is standard operating procedure.