Meta Ads ROAS Misreported? GA4's utm_medium Regex Silently Reclassifies Paid as Organic

Marketing teams using utm_medium=social for Meta Ads are unknowingly misclassifying paid clicks as organic traffic in GA4 due to a specific regex rule. This silent miscounting suppresses ROAS metrics and distorts marketing ROI reporting, potentially leading to budget allocation errors. The fix requires switching to utm_medium=cpc to align with GA4's official Paid Social classification regex.