Google confirms a Search Console logging error is deflating AI and Discover data from 13 August

Google confirmed on 17 August 2026, through John Mueller and two entries on its Search Console data anomalies page, that a logging error is deflating reported impressions and clicks for data from 13 August 2026. Search Engine Roundtable reported the confirmation the same day. Mueller's exact words on Bluesky were: "we're aware of this issue and working on resolving it. This is just a logging issue and not representative of visibility changes in Search. We're adding an annotation in Search Console to let folks know about this in the near future."

One distinction is worth making before anything else, because the two things are being merged. The Generative AI performance report in Search Console is not new. It finished reaching every property on 12 August 2026, and that was already reported. What is new is that the first substantial dataset the report has produced is unreliable. The report exists; the numbers it showed from 13 August do not describe what happened in Search.

What site owners saw in Search Console from 12 August 2026

Site owners began reporting sharp, widespread drops in Search Console impressions and clicks from around 12 to 13 August 2026, hitting both the Search performance report and the newer Generative AI features report. Glenn Gabe flagged clicks dropping from 12 August on X while third-party visibility tools and analytics platforms showed no matching decline. The same cliff-edge pattern appeared in reports on Bluesky, on LinkedIn and in the Google Webmaster Forums, across many unrelated properties at the same time. Google's Dave Smart replied in the forum that he suspected partial data for some days and escalated the reports.

The simultaneity across unrelated sites is the part that ruled out a normal ranking event early. A ranking change moves some sites down and others up, and it does not arrive on the same day for properties in unrelated markets with unrelated content.

What Google put on its data anomalies page

Google posted two separate entries to its data anomalies page after Mueller's confirmation, and they cover different reports on different terms. Merging them produces a wrong reading, so here they are as Google wrote them.

Read the two entries carefully, because the wording differs in three ways that matter. The first entry is about Generative AI in Search, says impressions, says data starting on 13 August, and is marked ongoing. The second entry is about Discover and Generative AI in Discover, says clicks and impressions, and says data on 13 August rather than starting on 13 August. They are not one incident described twice, and quoting one as if it covered both overstates or understates the window depending on which way you get it wrong.

Why a logging error is not a ranking drop

Mueller's confirmation on 17 August 2026 draws the line explicitly: this is a logging issue and not representative of visibility changes in Search. The mechanism is worth understanding rather than taking on trust, because it changes what you do next.

Search Console reporting is downstream of serving. When a page is shown in a result, an impression event has to be logged, aggregated and written into the property's performance data before you ever see it. Rankings, clicks by real people, and revenue all happen at serving time and are unaffected by whether the logging pipeline recorded them correctly. A logging error therefore changes the reported number while leaving the underlying event intact. Your pages were shown the same number of times; Search Console counted fewer of them.

The practical consequence is that no site-side action fixes this, and no site-side action is needed. There is nothing to resubmit, nothing to reindex, and nothing to roll back. Analysis: the real risk in an incident like this is not the missing data, it is the decisions made from it, because a fabricated cause gets attached to a fabricated effect and the site gets changed for no reason.

Why third-party tools showing no decline is the corroborating signal

Glenn Gabe's observation that third-party visibility tools and analytics showed no corresponding decline while Search Console clicks fell from 12 August 2026 is the single most useful cross-check in this incident, and it is one any site owner can run for themselves.

Rank trackers measure the SERP directly by querying it, and analytics platforms measure sessions on the site from the browser. Neither of them reads Search Console's pipeline. When Search Console alone shows a cliff and both independent measurement systems stay flat, the discrepancy sits in the reporting layer, not in Search. If all three moved together, the conclusion would be the opposite and this would be a real visibility event.

This is worth keeping as a standing method rather than a one-off. Any time a single data source shows a dramatic change, the first question is whether an independent source measuring the same underlying reality agrees.

What to do before month-end reporting

The affected dates from 13 August 2026 sit in the middle of the reporting month, which means the August report is the one that carries the damage. This is the practical checklist.

• Annotate the affected period in the report itself, naming the Search Console logging error and the 13 August 2026 start date, so the dip is explained on the page where a client will see it.
• Cross-check GA4 sessions from organic search over the same days. If sessions held while Search Console clicks fell, that is your evidence.
• Cross-check rank tracking for the same keywords over the same days. Flat positions plus falling reported clicks points at logging.
• Do not restate an AI-impressions decline as a finding. Any decline in Generative AI impressions from 13 August is inside the window Google flagged as corrupted.
• Hold off on setting an AI-visibility baseline from August data. The dataset most people would have used for it is the one Google says is wrong.
• Do not attribute the dip to a content change, a migration or a technical release that happened to ship in the same week. The coincidence is what makes this dangerous.

Analysis: the timing is unkind. The Generative AI performance report only reached every property on 12 August 2026, so for most site owners the corrupted days are close to the first data they ever had on their AI Overviews and AI Mode impressions. There is no clean earlier period to compare against, which removes the usual way of spotting that a number is off.

What Google did not say

Google confirmed the logging error but stopped there, and the gaps are as important as the confirmation. Google did not state a cause for the logging error. Google did not give a date or an estimate for a fix, and the first anomaly entry describes the issue as ongoing rather than resolved. Google did not say whether the missing impressions and clicks will be backfilled into the reports once the issue is fixed, or whether the affected days stay permanently understated. Mueller said an annotation would be added in Search Console in the near future, without a date.

Do not fill those gaps with a guess. Whether the data returns changes how you handle the August report, and there is no basis in anything Google published for predicting it either way.

What this means for Thai marketers

Thai agencies running client reports on a calendar month cycle will meet this incident at exactly the wrong moment, because the affected dates from 13 August 2026 fall inside the August reporting period and the report gets built in the first days of September. A Thai property showing an AI-impressions collapse in the second half of August should be checked against GA4 and rank tracking before anyone blames a content change, a template change or a technical release.

The wider point for Thai brands is about measuring AI search at all. Interest in AI Overviews and AI Mode visibility here is running ahead of the measurement, and Search Console's Generative AI report was the first free, first-party source of that data for Thai properties as much as for anyone else. This incident is a reminder that a young report is a young pipeline, and that an AI-visibility programme built on one data source is one logging error away from a wrong conclusion. If you are formalising how you measure AI search visibility, build it on at least two independent sources from the start.

Google made no statement about Thailand, Thai-language properties or any specific market in either anomaly entry. The entries describe reports, not regions.

FAQ about the Search Console logging error

Did my site actually lose traffic from 13 August 2026?

Not according to Google. John Mueller said the drop is a logging issue and not representative of visibility changes in Search, so the impressions and clicks happened and were undercounted. Check GA4 sessions and rank tracking for the same days to confirm it for your own property.

Which reports are affected?

Google's two data anomalies entries name the Generative AI performance report in Search for data starting on 13 August 2026, and the Discover performance report for data on 13 August 2026, including Generative AI in Discover impressions for properties with access to those features. Site owners also reported drops in the main Search performance report.

Do I have to do anything to fix it?

No. This is an error in Google's logging, not on your site, so there is nothing to resubmit, reindex or roll back. The only work is on the reporting side: annotate the period and avoid drawing conclusions from the affected days.

Will the missing data be added back later?

Google did not say. Neither anomaly entry states whether the impressions and clicks will be backfilled once the issue is resolved, and no fix date was given, so treat the affected days as unreliable rather than as either permanent or temporary.

Does this affect Thailand?

Google did not mention any country. The two anomaly entries describe reports and data types rather than regions, so Thai properties are affected on the same terms as any other property using the reports named, and no Thailand-specific statement exists.

If you are about to send an August report with an unexplained dip in it, or you are building an AI-visibility baseline that this incident just undermined, the SEO team at Relevant Audience can help you separate the reporting artefact from the real movement.