That coating is coming off, not the leather.

Your bag isn’t rotting—it’s the top finish peeling. Most Coach bags (especially in lighter colors and smooth leathers) have a protective coating that can delaminate with sweat, heat, or friction.

You can’t really “fix” it with conditioner or polish—that just sits on top. If it’s a recent purchase, Coach’s repair program is your best bet. They’ll re-dye or recoat it for a fee (or sometimes free if it’s a defect). If you’re out of warranty, Angelus leather paint or a professional leather restorer can match the color.

But don’t scrub it or try to peel it off yourself—that makes it look worse. Your next bag: buy unfinished leather (pebbled, natural) and avoid that plastic coating altogether.