This data logging issue was on July 26, 2022 - any drops in clicks or impressions might be just a reporting bug.
Google had a data logging error that impacted the Discover performance report in Google Search Console. This occurred on July 26, 2022 and may result in a drop in the number of clicks and impressions that Google logged.
This did not impact your rankings or visibility, it was just a reporting glitch.
The issue. Google wrote that on July 26 “due to a logging error, site owners might see a drop in their Discover clicks and impressions during this period. This is only a logging error, it is not a drop in actual views or clicks.”
Reporting issue only. Again, this did not impact your visibility in Google Discover, it is just an issue with reporting and data logging. So it may appear like you saw a drop in visibility but in reality, it was just an issue with Google’s reporting engine.
Here is a screenshot showing the annotation Google put on the report:
Fix coming? There does not appear to be a fix coming to replace the data, it seems like the data is gone and you will just have to annotate the date and move on.
Discover is hard. As a reminder, Google Discover traffic is super volatile, and thus, seeing massive spikes or massive declines in your Discover clicks and impressions is normal. So the loss of this data will be hard to backward engineer for any marketer or SEO.
Why we care. This is important for you to know and communicate to your clients, boss, stakeholders, etc when providing these reports to your client. So make sure to annotate the chart, which Google did for you, and then communicate these issues when presenting them to others.