Your favicon changed. Why is the old one still there?
A browser tab and a Google search result are separate checks. First prove that the right file is being served; only then investigate caching or search crawling.
Open the exact file URL
Copy the icon URL from the page’s rel=icon link and open it directly. A missing file, HTML error page or old image points to a deployment or path problem. Check the live homepage, not just a local preview. In a subdirectory installation, confirm that an initial slash is not pointing at the wrong folder.
Make one deliberate browser test
Check for competing icon declarations in the page head, CMS or theme. Different sizes or formats may make the browser choose another file. Test in a fresh browser profile. For a controlled deployment, change the filename once and update the link, then verify that this new URL serves the intended image. Avoid repeatedly renaming files as a substitute for diagnosis.
Treat Google as a separate system
Google needs access to both the homepage and icon, uses one favicon per hostname and recommends a square image larger than 48px. A subfolder does not get its own search favicon. Keep the chosen URL stable, check crawler access and allow for recrawling. Meeting the requirements does not guarantee display; reconverting the same image cannot force Google to refresh.