Meta advertisers using Conversions API (CAPI) are currently facing a significant technical issue. A deduplication bug has emerged where browser and server events such as 'Purchase' and 'AddToCart' are no longer being properly deduplicated in the platform's systems.
The problem began affecting Meta accounts around March 16, 2025, causing key events to be counted twice - once via the Meta Pixel (browser-side) and again through the server-side CAPI. According to reports, the issue stems from missing event_id values, which prevents Meta from properly matching pixel and server events.
Affected event types include:
- AddToCart
- Purchase
- PageView
- Other conversion events
Impact on Advertisers
This bug is creating several significant problems for advertisers:
- Inflated metrics showing doubled event counts, distorting campaign performance data
- Attribution issues making it difficult for Meta to accurately attribute conversions
- ROI analysis complications due to unreliable conversion tracking
Verification and Solutions
Advertisers can confirm if they're affected by opening Meta Events Manager and checking for reports of this issue starting from March 16.
For those experiencing this problem, Meta has suggested two potential interim solutions:
- Wait for resolution - Meta is expected to address this issue soon
- Disable server-side tracking temporarily - Maintain only browser events until the bug is fixed to prevent duplicate event counts
The issue appears to be on Meta's end, and the company is presumably working to resolve the deduplication problem affecting its advertising infrastructure.
