GTM-P6X398R

Whydocument.write blocks the HTML parser while it runs, and browsers ignore it entirely once the page has finished parsing — so an async-loaded tag using it can silently do nothing.

CheckIf these tags fire on page load they are costing render time; if they fire later they may not be working at all. Worth confirming the tag still does what it was added to do.

Seenseen in 18.4% of 46,522 containers measured

WhyCookies set this way bypass GTM's consent settings, because the consent checks live in the tag templates rather than in raw JavaScript.

CheckIf any of these cookies are used for analytics or advertising, confirm they are still gated on a consent decision.

Seenseen in 21.2% of 46,522 containers measured

WhyOn an https:// page the browser blocks or upgrades these. Blocked means the tag quietly stops working; upgraded only works if that host also serves https.

CheckCheck whether the hosts below still respond over https, and update the URLs.

Seenseen in 12.8% of 46,522 containers measured

WhyA conversion ID plus label identifies one action. Two tags carrying the same pair can report the same conversion twice, inflating conversion counts and the ROAS that bidding runs on.

CheckCheck whether both tags can fire on the same page. If they can, your Ads reporting is overstating this action and automated bidding is optimising against it.

Seenseen in 3.8% of 46,522 containers measured

WhyGTM shows you where a variable is defined, never how much depends on it. Editing this one touches a large share of the container at once, and whatever breaks will surface somewhere that looks unrelated to the change.

CheckBefore changing it, check what reads it. If it feeds both measurement and consent or routing logic, split those uses apart first.

Seenseen in 10.1% of 46,522 containers measured

WhyWhatever that host serves executes with full access to the page — it can read the DOM, cookies and form fields. The code is not in this container, so it can change at any time without any change here.

CheckConfirm you recognise every host below and that someone owns the relationship. A host you cannot name is the one to chase.

Seenseen in 54.4% of 46,522 containers measured

WhyBrowser storage persists across visits and is not covered by cookie consent tooling, so it is easy to overlook when auditing what you keep on a visitor's device.

CheckConfirm nothing personal is being kept there, and that it is covered by your privacy notice.

Seenseen in 23.3% of 46,522 containers measured

WhyConsent handling is present in the container. This describes what the artifact declares; what actually happened on the page is measured separately, above.

CheckConfirm these settings match the consent policy you intend to enforce, and compare them with the before-and-after observation.

Seenseen in 44.6% of 46,522 containers measured

WhyChanging a property, pixel or account then means editing every tag that mentions it, and any one that gets missed keeps sending to the old destination indefinitely.

CheckFine if the ID never changes. If you have ever migrated a property, check that none of these still point at the old one.

Seenseen in 31.4% of 46,522 containers measured