Looking on a printout I made in FamilySearch a year or two ago. It gave me nine results.
Find option gives me 56K results to look through.
@eljhm If you provide the Person ID we can go back and try and recreate your search.
I'm wondering if it was not actually a search result as such, but, say, the compare-and-add function on an uploaded file in Genealogies, or something gotten to when adding a profile in some way?
But, in any case, as Scott says, specifics would make it a whole lot easier to figure things out.
One place to find the "Ancestors in the shared tree" is by searching for a person by name in the Family Tree app—at the top is a list of people who meet the search criteria with brief information
Below are some historical records containing the name
I'm fairly sure that "People Found in the Shared Family Tree" heading used to be on the results screen for the Find Similar People search routine located in the Tools section of a person's detail page. That link also used to give far fewer results than the Find routine. Looking now, that heading is gone and although it may just be the person I tried it on, it appears the results are just as broad as the Find routine now.