Meta Ads receives ma conversion event but doesn’t attribute it correctly

Hi everyone,

I’m facing a strange Meta Ads attribution issue.
My website sends a custom event called Lead_Simulateur.

Here’s what I’ve verified :
- Pixel is working
- Conversions API is working
- Test Évents work perfectly
- Event Match Quality is good
- My ad sets are optimized for Lead_Simulation

However :

- Some campaigns show «—» instead of Results.
- Évents are received in Évents Manager but are not consistently attributed in Ads Manager
- Historical results sometimes change after simply refreshing The page

I’ve already checked GTM, consent mode, CAPI, deduplication and Pixel implémentation.

Hand anyone experienced something similar ? could This be an attribution / reporting issue ont Meta’s side ?