Attribution Window Mismatch
Google Ads, Meta, and TikTok each use different default attribution windows — 30-day click for Google, 7-day click and 1-day view for Meta, and a 7-day click window for TikTok. When a user touches all three platforms before converting, every platform counts the conversion within its window. A single conversion can be claimed by all three simultaneously. The combined reported conversion volume across your platforms is structurally inflated before any configuration error enters the picture.