In all my years of running sites and doing some fairly decent #SEO, I have never seen this issue before. Anybody have any thoughts here? The sitemap is correct, no pages have been deleted, and Google reports no issues with anything.. It just decided it no longer sees the rest of the sitemap?

Additional notes: I did request indexing for a handful of pages that it's not "seeing" a few weeks ago, too, and page interlinking is all good as well.