How to troubleshoot duplicate Shopify GA4 purchase event triggers in the pixel code?

Once, my DTC store's GA4 order count was nearly 20% higher than the Shopify backend. The ad team initially thought attribution had improved, but in reality, the purchase event was triggering repeatedly. When troubleshooting, I first used Tag Assistant and the browser's network tab to see exactly how many times the event was firing on the thank you page. I later discovered a hardcoded gtag…