Google has confirmed it had a reporting issue in the Google Search Console Performance Report for Discover traffic. Google said the issue was on July 26th and may result in a drop in clicks and impressions on or around that date.
Google posted that on July 26, 2022 “due to a logging error, site owners might see a drop in their Discover clicks and impressions during this period.”
Google said this is not a ranking issue or any true issue with the performance of your Google Discover traffic. “This is only a logging error, it is not a drop in actual views or clicks,” Google added.
So if you see weirdness in your Google Discover reports in Google Search Console around July 26th, it is likely related to this data logging bug.
Note, I do not see an annotation yet in the Search Console report, but I am sure it will show up eventually.
Forum discussion at Twitter.