Broken Meta CAPI dedup is silently doubling Shopify conversions and inflating ROAS
Deduplication is the quietest way to wreck paid attribution. When a browser pixel and server-side CAPI event fire for the same purchase without matched event IDs, Meta counts one sale twice — and reported conversions inflate in lockstep. Audit your Shopify pixel and CAPI keys against a plain order count: if Meta's number is systematically higher, your ROAS is a lie and your bidding is scaling on synthetic signals.