GTM purchase event vanished after publish: what I check

You hit Publish in Google Tag Manager. The version went live. Then purchase events quietly disappeared from GA4 or your ads dashboards. Orders are still coming in. The container just stopped telling anyone about them.

I see this a lot on WooCommerce sites. Here is the order I check things in before I start rewriting tags from scratch.

Confirm which container is actually live

Preview mode can look fine while the live site is still on an older published version, or on a different container ID entirely. Open the thank you page with Tag Assistant, note the container ID, and match it to the workspace you just published. Staging and production containers getting mixed up is more common than people admit.

Open the version you published, not the draft

In GTM, go to Versions and open the exact version that is Live. Compare the purchase tag, its trigger, and any consent or exception settings to what you thought you changed in the workspace. Unpublished workspace edits do nothing on the live site. A publish that only included half your changes is easy to miss when a few tags are paused or filtered out of the version.

Triggers that worked yesterday

• Thank you page path changed after a theme, plugin, or gateway update
• Trigger now looks for a data layer event that the theme stopped pushing
• Page Path equals a hard-coded URL that no longer matches (trailing slash, query strings, localisation)
• An exception trigger started matching every order-received hit

Fire a real test order and watch Preview against the live thank you URL. If the trigger stays red, the tag never stood a chance.

Paused tags and consent

Publishing does not un-pause a tag. Check the purchase tag is still active. Then check Consent Mode and your cookie banner: a new default denied state, or a CMP change that landed in the same publish, can block purchase until consent is granted. That looks identical to "the event vanished" if you only look at aggregate numbers.

Data layer and value fields

Sometimes the tag fires but the event is useless. Missing transaction_id, value, or currency means GA4 or Google Ads may drop or ignore it. Check the data layer on order-received for the keys your variables expect. Variable renames in a "tidy up" publish are a classic way to break a working purchase tag without touching the trigger.

Duplicates, old hard-coded pixels, and cache

Two purchase tags, or a leftover hard-coded pixel fighting GTM, can make reporting look broken even when something is firing. Full page cache on the thank you page can also serve a shell with no tags. Purge cache for checkout and order-received, then retest in a private window.

If ads numbers are still quiet after GTM looks healthy, I walk the wider conversion path here: Woo ads conversion not recording: what I check first.

Get one clean purchase event on a real order-received page after the Live version, not only in Preview. Then trust the dashboards again.