Windows search for text in files returns unrelated files

I am trying to find some Excel files that have text in them, say “LON, NON” in a cell.

In Windows Explorer, I go to the folder with the files, and do a search: content:"LON, NON"

I start getting results, but so far the (dozens of) files it has found do not have LON, NON anywhere in the file. (I’ve also tried just using the search term "LON, NON" [removing the content:] but same issue.

Why is it returning these? Is Windows search effectively broken these days? Am I missing a flag to use?

FWIW: The files are on OneDrive I believe, C:Users1234OneDriveHomeDrive_Users123Data