What Does NOT Work: AI Max for Search Failure Modes — where the opt-in that Google turns on for you burns budget and copy control

AI Max for Search is a bundle of automation settings layered onto a Search campaign — search term matching, text customization, and final URL expansion — and its failure modes come from three facts advertisers underestimate: two of the three settings are turned on by default the moment you enable AI Max, the "brand controls" don't do what the name implies, and on a fixed 2026–2027 calendar Google auto-upgrades DSA / ACA / broad-match campaigns into it whether or not you opted in. Each mechanic below is traced to Google's own documentation; where the folk version of a risk is stronger than what Google actually documents, the folk version is dropped and the documented one recorded instead.

Final URL Expansion Redirects Traffic Off Your Chosen Landing Page — On by Default

The trap: you set a final URL, but the ad can serve a *different* page on your domain, and you didn't turn that on deliberately.

- Enabling AI Max turns on both text customization and final URL expansion for the campaign by default: "Turning on AI Max will turn on text customization and Final URL expansions for the campaign to optimize the user experience. You can toggle them off individually in campaign settings." If you enable AI Max without opening settings, FUE is already live. — https://support.google.com/google-ads/answer/15910187 - What FUE does: "Send traffic to the most relevant URLs on your website when it's likely to result in better performance. Final URL expansion will only send traffic to URLs that are query relevant and themed to your ad group." The landing page is chosen by the system from across your domain, not fixed to your final URL. — https://support.google.com/google-ads/answer/15910187 - Documented breakage, not folklore: dynamically expanded URLs "can sometimes lead to broken expanded landing pages with a 404 error if the tracking templates aren't configured in a compatible way." Google's own instruction is to "verify that a dynamic landing page from AI Max's final URL expansion (FUE) works on your landing page before enabling AI Max." — https://support.google.com/google-ads/answer/15910187

How to avoid it: before enabling AI Max, decide whether FUE should be on at all, and if it is, constrain it. Google provides URL exclusions — "Exclude specific URLs from serving as landing pages in your campaign" (campaign-level) — and URL inclusions to "include URLs that were not captured by final URL expansion." — https://support.google.com/google-ads/answer/15910187 If any URL in the campaign carries a tracking template, test the expanded/dynamic landing page for a 404 first, since incompatibly configured templates are the documented cause (same source). If you need the ad to land only on the page you specified, toggle FUE off in campaign settings.

(dropped) The stronger claim that FUE sends paid traffic to *unapproved pages without required disclaimers*, creating a compliance/suspension risk, is not stated in either Google source and is not recorded here as fact — the documented risks are the 404 breakage above and the pinned-asset bypass below.

Final URL Expansion Silently Overrides Your Pinned Assets

The trap: you pinned a headline (a legal line, a disclaimer, the exact brand phrasing) expecting it to always show — and FUE drops it.

- "When Final URL expansion is turned on for your campaign, pinned assets aren't used if a more relevant URL is chosen, because they may not match the customer's intent." — https://support.google.com/google-ads/answer/15910187

How to avoid it: treat pinning and FUE as mutually exclusive for anything that must always appear. If a headline or description is non-negotiable (regulated wording, mandatory disclaimer, brand-mandated phrasing), do not rely on pinning while FUE is on — turn FUE off for that campaign, or move the required copy somewhere the system cannot drop. See How to Write Ads That Don't Get Disapproved (or Worse) — the checks that separate a fixable rejection from an account-ending one for where mandatory copy has to live.

Text Customization Generates Ad Copy You Didn't Write

The trap: AI Max rewrites the impression away from your approved copy toward generated text.

- Text customization "Uses text from your existing ads, landing page copy, and assets along with generative AI for Google Ads to create customized ad copy that's more relevant to specific user searches." It creates ad copy; it is not limited to serving the assets you typed. — https://support.google.com/google-ads/answer/15910187 - It is on by default with AI Max (same toggle statement as FUE above). — https://support.google.com/google-ads/answer/15910187

How to avoid it: AI Max exposes text guidelines as a control to "steer AI with greater precision," alongside brand and location controls — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/ — so if you keep text customization on, set the text guidelines rather than leaving generation unconstrained. If your vertical can't tolerate machine-generated headlines/descriptions at all, toggle text customization off in campaign settings. How to Write Ads That Don't Get Disapproved (or Worse) — the checks that separate a fixable rejection from an account-ending one governs what the generated copy must and must not say.

"Brand Controls" Don't Restrict Which Queries You Match

The trap: the setting is labelled brand-safety, so advertisers assume it keeps them off competitor and off-target searches. It doesn't — it governs brand *association*, not query matching.

- Brand controls "Specify the exact brands you want your ads to be associated with (brand inclusions), or prevent your ads from appearing alongside specific brands (brand exclusions)." These are content-association controls — which brands your ads appear next to — not URL controls and not query-matching controls. — https://support.google.com/google-ads/answer/15910187 - Their scope: "Brand inclusions: Campaign and ad group level control. Brand exclusions: Campaign level control." — https://support.google.com/google-ads/answer/15910187 - Query breadth in AI Max is governed by a separate mechanism, search term matching, listed as a distinct AI Max feature — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/ — which "you can expand upon your existing keywords using broad match and keywordless technology to find more relevant and high-performing search queries." — https://support.google.com/google-ads/answer/15910187 Brand controls do nothing to narrow it.

How to avoid it: don't treat brand controls as a query filter. To stop matches on competitor or irrelevant queries under AI Max's broad search term matching, you still need the ordinary negative-keyword discipline — see How to Do Keyword Research and Build a Negative Keyword List — closing the leak Smart Bidding can't see and the broad-match failure patterns in What Does NOT Work: Broad Match and Smart Bidding Without Guardrails — where automation burns budget instead of saving it, which apply directly to AI Max's expanded matching.

(corrected) An earlier framing said brand controls "restrict only domain paths." Google's definition is narrower still: they restrict brand *association*, not paths (that's URL exclusions) and not queries (that's negatives). Recorded above in Google's terms.

Forced Migration: The Upgrade You Don't Choose

The trap: even if you never enable AI Max, Google migrates your existing automated Search campaigns into it on a fixed timeline, inheriting every default above.

- New DSA creation stops in September 2026: "Starting in September, remaining eligible Search campaigns with legacy settings will automatically upgrade to AI Max, and you won't be able to create new campaigns with DSA via Google Ads, Google Ads Editor and the Google Ads API." — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/ - ACA and campaign-level broad match auto-upgrade starting September 2026: "campaigns using Automatically Created Assets (ACA) and campaign-level broad match setting will continue to be auto-upgraded starting in September 2026." — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/ - DSA auto-upgrade was pushed to February 2027 — "we are extending the timeline for Dynamic Search Ads sunset and auto-upgrade, which will begin in February 2027." So DSA campaigns themselves are not upgraded in September 2026; that date covers ACA / broad-match upgrades and the end of new-DSA creation. — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/ - What the source does not say: it gives no formal date on which existing DSA campaigns are deleted or disabled — only that new-DSA creation ends and auto-upgrades occur on the dates above. Don't assert a "DSA delete date." — https://blog.google/products/ads-commerce/dsa-upgrade-to-ai-max-2026/

How to avoid getting surprised: inventory every DSA, ACA-using, and campaign-level-broad-match campaign now, and diary the two dates — September 2026 (ACA / broad-match upgrades and end of new-DSA creation) and February 2027 (DSA sunset / upgrade). When a campaign is upgraded it inherits FUE and text customization on by default, so the day it migrates is the day to open campaign settings and apply the guardrails in the sections above (FUE off or URL-constrained, pinned/mandatory copy protected, text guidelines set, negatives in place). See Google Ads Campaign Types: What Each One Is For — Picking the Right Inventory Before You Set Up or Audit an Account for where DSA sits among campaign types being consolidated into AI Max.

Related

- What Does NOT Work: Broad Match and Smart Bidding Without Guardrails — where automation burns budget instead of saving it — AI Max's search term matching is broad matching under a new name; the thin-data, learning-reset, and query-breadth failure modes there apply unchanged, and campaign-level broad match is one of the settings auto-upgraded into AI Max. - What Does NOT Work: Performance Max Failure Modes — the same automation family: defaults you didn't set, query-level blind spots, and brand settings that don't cover the channels you assume; read alongside this page to see the pattern across Google's automated products. - What Does NOT Work: Letting an API/Script Agent Run Unsupervised — the Actions That Need a Human Checkpoint — the general rule this page instantiates: automation that is on by default has to be audited and constrained, not trusted. - How to Write Ads That Don't Get Disapproved (or Worse) — the checks that separate a fixable rejection from an account-ending one — where mandatory/regulated copy must live, given that FUE can drop pinned assets and text customization can generate copy you didn't write. - How to Do Keyword Research and Build a Negative Keyword List — closing the leak Smart Bidding can't see — the actual lever for narrowing AI Max query matching, since brand controls do not do it. - Google Ads Campaign Types: What Each One Is For — Picking the Right Inventory Before You Set Up or Audit an Account — situates DSA within the campaign types being folded into AI Max on the September 2026 / February 2027 timeline.

Why this page matters for the objective

AI Max is the setting most likely to spend budget and alter creative in ways the advertiser never explicitly approved — two features on by default, a brand-safety label that doesn't filter queries, and a forced-migration calendar that applies all of it to accounts that never opted in. Knowing exactly which defaults fire, and which Google-documented controls switch them back off, is the pre-flight guardrail the wiki's objective calls for — auditing and optimizing without waste, before the migration does it for you.