There are widespread reports of webmasters complaining that the sitemap report in the Google Search Console shows a significant drop in the number of pages indexed over the past 24 hours.
Many webmasters see in this report that the number of pages Google says they have indexed on their website is now about 25 percent lower than it was the day before. Of course, the fewer pages indexed, the less opportunity to rank for more pages and keyword phrases.
Here is a screen shot of my report, but all the screen shots I’ve seen circulating look similar:
Google has not commented on this issue, but I wanted to report it so those who are worried can know they are in good company and that this seems to be a bug on Google’s end.