The nightmare:Clicks continue, spend continues, but recorded conversions suddenly fall. The immediate conclusion is usually that the campaign has stopped converting. That may be true, but it should not be the first assumption.
What may actually be happening:A conversion can disappear at several points in the attribution chain. A click identifier may not be passed through a redirect. A postback may fire without the correct transaction ID. A conversion event may have been changed, duplicated or unpublished. A thank-you page may load without the required tag, or a domain migration may leave the tracking code on the old URL.
Google’s Tag Diagnostics documentation specifically recommends checking tag coverage after domain changes, redirects and thank-you-page updates. The same principle applies beyond Google Ads: every identifier and event must survive the complete journey from click to conversion.
What to check first:Run a controlled test using a unique click or transaction identifier. Confirm that the identifier appears in the landing-page URL, reaches the conversion event and returns to the tracking platform. Compare raw click logs, conversion logs and postback responses rather than relying only on dashboard totals. Check timestamps and time zones before declaring a discrepancy. A reporting delay or different attribution window can make two valid reports look inconsistent.
How to reduce the risk:Keep a documented test path for every active campaign. Test after any change to a domain, landing page, form, redirect, tracking template or conversion event. Automated alerts should flag unusual changes in conversion rate, but they should support, not replace an end-to-end test.