I remember a campaign on Instagram: strong creative, good traffic, high expectations.
But GA4 showed strange results - low conversions, weak engagement. The traffic came mostly from iOS Safari via Instagram’s in-app browser.
That’s when it clicked: iOS or AdBlock = probably invisible to GA4.
Why?
• Safari in lot of cases blocks third-party cookies via ITP
• Instagram opens links in in-app browsers — scripts and UTMs often break
• AdBlock can block GA4 entirely — events never send
• Redirects strip UTMs — source attribution is lost
• If the user closes the tab quickly, GA doesn’t fire in time
Result: no session. No purchase. No client ID. The user exists — but GA4 can’t see them.
In this case:
• GA4 shows only part of real traffic
• The campaign looks like a failure
• But CRM and payment logs showed steady orders — GA4 just misses them
• Without cross-checking, a working campaign would've been shut down
It isn’t a broken setup — it iss browser-level blocking.
Now, if a campaign involves iOS or social traffic, I always:
• Mirror key events (purchase, lead) via Server-Side tracking
• Use first-party cookies — they survive longer i
• Test for UTM stripping in in-app browsers (Instagram, TikTok)
• Compare GA4 with CRM and server logs
GA4 isn’t broken. It simply can’t see what the browser hides.
But if you trust it blindly — you might turn off what’s actually working.
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