Yes, this is a known issue that many advertisers face when using both Pixel (browser-side) and CAPI (server-side) tracking—especially with platforms like Go High Level (GHL).
Below are insights and recommendations:
1. Event Deduplication Conflict:
When both Pixel and CAPI send the same event without proper event_id matching, Meta may count only one or none due to deduplication confusion.
If CAPI sends an event without the correct matching parameters (event_id, fbclid, fbp, etc.), Meta might ignore the custom conversion.
2. GHL Automations Often Miss Metadata:
GHL sends basic event data, often missing necessary deduplication metadata like fbp, fbclid, or event_id.
3. Turning Off CAPI May Restore Functionality:
As you've seen, going back to Pixel-only can make custom conversions appear again, since deduplication isn’t triggered.
How to Fix or Properly Manage CAPI Without Breaking Custom Conversions:
1. Always Use Matching event_id
Your browser (Pixel) and server (CAPI) event should send the same event_id for deduplication.
This prevents duplication while allowing both systems to work together.
2. Pass fbp and fbclid to CAPI
Capture and store these browser parameters in your forms or CRM.
Pass them back via CAPI for better attribution and deduplication.
3. Use Event Testing Tool
Use Meta Events Manager > Test Events to confirm whether CAPI and Pixel are firing correctly and being deduplicated properly.
4. Use GHL Only for Events That Don't Fire from Pixel
For example: use CAPI for Purchase or backend-triggered events, but not for PageView, ViewContent, or AddToCart, which are better captured via Pixel.