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When GA4 officially replaced Universal Analytics, many marketers rushed to migrate, fast. But two years later, most setups we audit still have fundamental issues. The result? Broken funnels, misattributed revenue, and hours lost trying to explain “why the numbers don’t match.”
A proper GA4 audit isn’t about fancy dashboards. It’s about ensuring every touchpoint, event, and parameter reflects reality. Here are the 10 mistakes we still see in 2025, and how to fix them before they quietly distort your performance data.
Wrong Property Configuration
Many teams track multiple brands or subdomains under a single property. This blends traffic sources and inflates metrics.
Fix: Use one property per website (or app) unless there’s a clear cross-domain journey. Review data streams under Admin → Data Streams and remove unnecessary ones.
Missing Key Events in the Funnel
We still see GA4 setups missing core events like add_to_cart, generate_lead, or begin_checkout. Without them, your funnel visibility is incomplete.
Fix: Compare your actual conversion journey to the events list in GA4. Implement missing steps via GTM, and mark the essential ones as conversions.
Duplicate Conversions Firing
Duplicate purchase or form_submit events are more common than you think, especially when GA4 and a CRM like HubSpot both send data.
Fix: Check Realtime or DebugView for duplicates. Use transaction_id or deduplication logic in GTM to prevent inflated ROAS.
No Cross-Domain Tracking
Users moving between your website, blog, and checkout on separate subdomains often get counted as new sessions. That breaks attribution chains.
Fix: In GA4’s Tag Settings, add all domains under Configure your domains. For complex cases, use GTM’s linker configuration.
Ignoring Consent Mode and Data Signals
With privacy tightening, missing Consent Mode or Google Signals means losing entire user paths, especially in the EU and U.S. states with new privacy laws.
Fix: Enable Google Signals under Data Settings and configure Consent Mode (v2) in GTM. This ensures modeled data continuity even when cookies are declined.
Broken Event Naming Conventions
Events like signup_button and sign_up both exist, tracking the same thing differently. It’s a reporting nightmare.
Fix: Create a single naming convention (e.g., snake_case) and maintain a shared event schema document for your team or agencies.
Mismatched GA4 and Ad Platform Conversions
Marketers often panic when GA4 reports fewer conversions than Meta or Google Ads. The cause? Different attribution logic and windows.
Fix: Align attribution windows (7-day click, 1-day view) across platforms. If possible, set up server-side GTM and conversion APIs to unify signals.
No BigQuery Export
Still relying only on the GA4 interface? You’re missing the source of truth. Without BigQuery, you can’t query raw event-level data or reconcile finance metrics.
Fix: Go to Admin → BigQuery Linking and export daily events. Even if you don’t use it today, having it stored saves headaches later.
Event Parameters Not Used in Reports
Teams set up rich parameters like product_category or campaign_type but never connect them to custom dimensions. The result: invisible insights.
Fix: Under Custom definitions, register all relevant parameters. You’ll instantly unlock granular views in Explorations and Looker Studio.
No QA or Monitoring Process
After setup, most teams never test again. Events break silently, especially after redesigns or tag updates.
Fix: Build a quarterly QA checklist. Test key events in DebugView, cross-check conversion rates in ad platforms, and use GTM’s version history to catch recent changes.
Bonus Tip: Standardize UTMs
Half the audit issues we find start with inconsistent UTM tags, fb / paid vs facebook / cpc.
Fix: Create a simple UTM governance sheet and require all teams to use it. Clean UTMs = clean attribution.
GA4 is powerful, but only when it’s clean. A proper audit ensures your campaigns, funnels, and revenue data tell the same story across every platform.
At Y77, we specialize in fixing data foundations before scaling paid media. If your GA4 reports don’t match your intuition (or your CFO’s spreadsheet), it’s time to audit.
→ Let’s fix your analytics foundation
