Google conversion tag firing 9× per checkout
Duplicate gtag snippets from a Shopify Customer Events template are firing the Purchase event 9 times for every completed checkout. Reported ROAS reads 4.10x; real ROAS is closer to 0.46x. Smart Bidding has been optimising for inflated outcomes for ~3 months.
Evidence
Sample of 23 orders pulled from `orders.landing_site` + `gtag` event count from `events_last_30d`. Reported conversions 207, real conversions 23. 9× duplication ratio.
The fix
1. Shopify Admin → Settings → Customer events. 2. Find the 'gtag' or 'Google tag' custom pixel. 3. Open the source. 4. Find any duplicate `gtag('event', 'purchase', …)` blocks. 5. Keep one; delete the rest. 6. Test by placing one order in incognito and watching Google Ads → Conversions in real time.