“postbacks are coming in delayed and you need to make sure that you're basically evaluating campaigns that way and always match data from two days back with the right spend level additionally I would say also give meta a little bit more time because they don't get these events super quickly so you shouldn't be evaluating results after three four days”

Never evaluate a new Meta campaign before 7 days — SKAdNetwork postback delay makes early data meaningless

SKAdNetwork postbacks arrive 2-3 days late, meaning a campaign launched Monday will not show trial events until Thursday. Pausing or killing a campaign at day 3 because it shows zero results is almost always a mistake — the data simply has not arrived yet. Burke's rule: wait at least 7 days and always compare spend levels to the correct 2-day-delayed event window.