Meta advertisers using Conversions API (CAPI) have encountered a deduplication bug leading to key events, such as purchases and add-to-carts, being logged twice. This includes once via the Meta Pixel (browser-side) and once again through the server-side CAPI.
The issue began over the weekend on the 16th of March 2025, due to missing event_id values. This prevented the exact matching of events, leading to inflated metrics, attribution errors, and unreliable ROI analysis.
For advertisers wishing to determine whether they have been affected by this issue, visit Meta Events Manager. To mitigate the impact of this bug, they can either wait for Meta to resolve it or temporarily disable server-side tracking to prevent further event deduplication.
