Google posted in the data anomalies page and on Twitter that it has updated the coverage report within Google Search Console and as a result, you may see more indexed pages being reported as of December 15, 2019. In short, some pages that were “Crawled – currently not indexed” are now known to be indexed.

Here is what this site’s report looks like, notice the spike in indexed pages on December 15th (click to enlarge):

Google wrote “The Index Coverage report can now more accurately report on indexed pages. Because of this, some pages that were Crawled – currently not indexed are now known to be indexed. As a result, you may see a transfer of pages from Excluded to Valid state. This does not reflect any changes in your site, but a more accurate accounting system.”

It makes you wonder – I mean – here, I’ll quote AJ:

In any event – if you see the change and your clients go – what is up – you can show them this.

Here is what others in the SEO community are seeing:

Forum discussion at Twitter.