Honestly, yeah, seen this a few times now. “Nothing changed” on your end and then the update still kicks you anyway. The annoying part is when indexation looks fine but the SERPs just shuffle like crazy for a week or two. I’d be looking at the usual suspects first — sitewide template changes from a plugin update, internal linking weirdness, or some crawl/render issue that only shows up after the algo refreshes. Wouldn’t assume it’s permanent yet, but 30% is enough to make you stare at Search Console like an idiot for a few days. Personally,