The conversion happened, but you see it in ads or GA4 hours — sometimes days — later. Before treating it as a bug, know that with ad systems delay is largely normal. Here's how to tell normal delay from a real problem.
Why delay is normal
- Data processing. GA4 standard reports need time (hours, fully stabilizing over 1–2 days). DebugView and realtime are instant, reports aren't. See GA4 reports vs realtime.
- Attribution window. Ad platforms credit a conversion to the click day, not the purchase day — so a conversion can "appear retroactively". See what an attribution window is.
- Modeled and imported conversions arrive with a lag.
When the delay is normal
If the conversion eventually appears (just not immediately) and the counts after processing match orders, all is well — it's processing and attribution, not a measurement bug.
When it signals a problem
- The conversion doesn't arrive at all even after a day — then the problem is in measurement. See GA4 not showing conversions.
- Counts after processing consistently don't match store orders (many missing) — typically client-side losses.
How to verify
Test via DebugView (instant) — if the event arrives there immediately, measurement works and the report delay is just processing. If it doesn't reach DebugView either, address measurement.