When SEO Tools Break and Rankings Shift — Lessons From September 2025

September 2025 was a month that reminded the SEO industry of something easy to forget: the tools we rely on to measure search performance are not infallible. A single technical change by Google on 10 September caused widespread disruption to rank tracking platforms including Semrush and Ahrefs, leaving many business owners and SEO professionals staring at data that looked alarming but was largely an artefact of broken reporting rather than actual ranking changes.

It had already been a volatile year for anyone watching rankings closely. The June 2025 core update alone kept the industry busy for weeks, and September piled tool problems on top of that algorithm noise.

At the same time, Google's August 2025 spam update was still rolling out — a broad update that began on 26 August and would not complete until 22 September, making it one of the longer update rollouts of the year. And AI Overviews were appearing in 44% of all Google queries, up from 26.6% in May 2024.

For businesses in Cairns and regional Queensland, September 2025 offers some useful lessons in how to read a volatile search environment without overreacting — and where to focus when the landscape is shifting.

What Actually Happened With the SEO Tools

On 10 September 2025, Google disabled the num=100 URL parameter — a technical feature that allowed users to request a search results page showing 100 results rather than the standard 10. Most human users had no idea this feature existed. But a significant number of rank tracking tools had been quietly relying on it to efficiently check where pages ranked across the top 100 positions.

When Google removed it, those tools lost their primary method of pulling ranking data. Semrush's tracking sensor showed a clear gap in data from 10 to 17 September. Google Search Console data appeared inconsistent during the same period. Impressions and position data looked strange across many accounts.

The important thing to understand is that this did not affect actual rankings. Your pages did not move. Google did not penalise anyone. The underlying data was unchanged — only the tools' ability to retrieve and display it was disrupted.

For business owners who check their rankings regularly, this is a useful reminder. Ranking data from third-party tools is a measurement of something real, but it is always mediated by the tool's methodology. When numbers move unexpectedly, the first question should be whether the tool is reporting accurately, not whether your site has been affected by an algorithm change.

Search Console, being a direct connection to Google's own data, is always the most reliable source when third-party tools are producing unexpected results.

The August Spam Update Kept Rolling

While the tool disruption was causing confusion, Google's August 2025 spam update was continuing its rollout in the background. This was a broad, general spam update — Google described it plainly as a normal spam update rolling out for all languages and locations.

The update hit hard and fast initially when it launched in late August, with some sites seeing ranking drops within 24 hours. Then, around 9 September, it intensified again, with further ranking fluctuations and indexing issues reported across the industry.

The pattern with spam updates is consistent: sites relying on tactics that violate Google's guidelines — keyword stuffing, manipulative link schemes, bulk AI-generated content without genuine oversight, thin pages produced at scale — are the primary targets. Sites publishing genuine, expert content with clean technical setups are largely unaffected or, in some cases, see improvements as competitors are demoted.

For regional businesses in Cairns and Far North Queensland, the practical takeaway from the August spam update completing in September is straightforward. If your website contains content that exists primarily to rank rather than genuinely help your customers, that content is a liability. Not because Google will necessarily catch it in any single update, but because the direction of Google's spam detection is consistently toward more sophisticated identification of low-value content, not less.

AI Overviews at 44% of Queries — What It Actually Means

Research published in September 2025 tracking queries from May 2024 found that AI Overviews had grown from appearing in 26.6% of searches to 44.4%. That is a substantial increase over roughly sixteen months, and it reflects Google's confidence in deploying AI-generated responses across a broader range of query types.

For businesses, the 44% figure requires context to be useful. AI Overviews are not distributed evenly across all types of searches. They are heavily concentrated in informational and research queries — the kinds of questions people ask when they are learning about something rather than ready to act on it.

Local and transactional searches — the queries most directly connected to customers finding and contacting your business — remain less likely to trigger an AI Overview. Someone searching for a specific service in Cairns, looking for a business to call, or trying to navigate to a local provider is still largely served by traditional results, map listings, and Google Business Profiles.

The implication for content strategy is one I have raised before, but September's data reinforces it: content that addresses the research phase of your customers' decision-making is now more likely to be absorbed into an AI Overview than to drive direct clicks. Content that addresses the decision phase — specific, locally relevant, clearly connected to your actual offer — remains a direct driver of customer contact.

The Broader Question of Discovery

September 2025 also surfaced a more uncomfortable conversation in the SEO industry. A large-scale study published during the month found that AI chatbots and generative search tools were sending users to significantly more broken links — 404 errors — than traditional Google search. This highlighted a structural issue with AI-driven discovery: when an AI cites a page that has since moved or been deleted, the citation remains but the destination is gone.

For businesses, this is a practical reminder to maintain clean URL structures and to avoid deleting or moving pages without proper redirects. As AI tools increasingly reference specific pages on your website in their responses, the durability of those URLs matters more than it used to.

It also raised a broader point about who controls discovery. As search becomes more AI-mediated — with Google, ChatGPT, Perplexity, and emerging AI browsers all playing a role — the concept of a single search engine to optimise for is becoming obsolete. Discovery is fragmenting across platforms, and the businesses best positioned are those with a coherent, well-structured online presence that works across all of them rather than one optimised narrowly for a single channel.

What to Actually Do With All of This

September 2025 was a month of noise. Tool disruptions, a long-running spam update, AI Overview data, and broader conversations about the future of search all competed for attention.

For a business owner in Cairns trying to run an actual business, the practical response to all of this is not to spend more time monitoring SEO dashboards. It is to build a presence that is resilient enough that a month like September does not require urgent action.

That means content that is genuinely useful and locally specific, not dependent on ranking tricks that any given update might target. A Google Business Profile that is accurate, active, and accumulating real reviews. A website with clean technical structure and durable URLs. And a realistic expectation that search data will be noisy at times, and that the signal worth paying attention to is the medium-to-long-term trend, not week-to-week fluctuations.

If you checked your rankings in September 2025 and saw unexpected numbers, there is a good chance the tools were at fault. If you saw a genuine decline that has persisted, it is worth investigating — but the investigation should start with your content quality and technical health, not a search for shortcuts.

If you want help making sense of what your data is actually telling you, I am happy to take a look.