My Experian score once took a substantial hit, dropping from ~800 to ~700 or something like that. Didn’t change elsewhere. I applied for the report and realized a quite significant debt appeared on my report, and it wasn’t even in my name! It was under someone else’s name that bore zero similarity to mine, or anyone in my family. Reported to Experian and it got fixed after a week or two. Zero explanation for how it happened. These credit reporting agencies are a joke.