Why do our webpages drop out of the index but return when resubmitted?

• Our site has a number of pages that have fallen out of Google's index only to return after being manually resubmitted. Then after a week or two later they fall out again.

  We've seen this process repeat itself several times and it's making us a little crazy. Do you know what might be the causing this?

Answer:

Chances are these webpages are teetering on what Google calls the edge indexing...

Yeah, that can happen. But it can also happen that it drops out again a week later, or a different URL drops out. If you're teetering on the edge of indexing, there's always fluctuation. It basically means you need to convince Google that it's worthwhile to index more.

— ◼️◼️◼️◼️◼️◼️◼️◼️◼️◼️◼️(@JohnMu) November 8, 2021

A while back Google's Gary Illyes posted a tweet about webpages on the edge of Google's quality threshold...

as we find new URLs, the page may fall out the index, but then you breathe new life into it temporarily by submitting to the index manually.

— Gary 鯨理／경리 Illyes (@methode) July 28, 2021

Strategically speaking, you might consider resubmitting these pages for temporary indexing to support an upcoming event or promotion. But in the long run you are better off by upgrading the quality of the pages.

The bottom line is; if you need to submit pages to Google manually in order to get them indexed, it's a good indication there's a quality issue with those pages.