Google had added two notations around specific data anomalies within Google Search Console with Web Stories. Both are related to Google Discover and Web Stories, one was related to the launch of Web Stories on Google Discover.
These impact the search performance reports and read:
- October 6, ongoing (Discover): Following the launch of the Stories carousel feature on Discover, you might see a significant increase in Web Story stats on Discover reporting for your site.
- September 25-28 (Discover): Web Stories were shown less often to Discover users during this period, so you will see a drop in impressions and clicks for this type in the Performance report for Discover.
So if you use Web Stories, take these data anomalies into account when reviewing your Search Performance reports in Google Search Console.
Forum discussion at Twitter.