Ah funny you mention that. Years ago I was doing tech support for a 3rd party ad management software mostly focused on Search (Google + Bing) but had also a FB

Ah funny you mention that. Years ago I was doing tech support for a 3rd party ad management software mostly focused on Search (Google + Bing) but had also a FB part. While digging into some discrepancy issues, I realised our own tracker was picking up way less clicks than what FB alleged. Across all the cases (a handful at best) I was involved in, this appeared over and over. I remember going back to our internal FB team highlighting that. Never heard back from them and had too much on my plate to bother with it. I'm glad to see I'm not the only one that picked up on that.